Relationship Satisfaction, Sexual Desire, Jealousy, and Conflict Resolution in Monogamous and Consensually Non-Monogamous Romantic Relationships

Abstract

Among the models of romantic relationships, consensual non-monogamy (CNM) is one in which several affective and/or sexual relationships are allowed simultaneously. This type of relationship, still considered non-normative, has experienced a considerable increase in recent years. However, research is still limited, and studies on the subject in Spain are scarce. To better understand the differences and similarities between monogamous and CNM relationships, this study investigated both relational models, divided by sex, for four factors concerning romantic relationships: relationship satisfaction, sexual desire, jealousy, and conflict resolution styles. In a sample of 210 persons, the results showed that CNM females reported significantly higher levels of consensus and dyadic sexual desire than monogamous females. Jealousy levels were similar in both types of relationships. People in CNM relationships displayed greater conflict resolution skills through negotiation and compromise, whereas monogamous females reported using the non-constructive style of conflict engagement more than CNM females and monogamous males. CNM males indicated a greater use of withdrawal compared to CNM females. Overall, females showed more passionate jealousy than males. This investigation highlights the importance of studying romantic relationships and their different models.

1. Introduction

When it comes to establishing bonds and romantic and affective–sexual relationships with other people, the most common and well-known model in Western culture today is still monogamy [1]. This model is based on the idea of affective and sexual exclusivity between two people. We could say that modern monogamy is constructed as a way of life in crises, and it is incapable of resolving internal tensions between institutionalized norms and the influence of modern values. As a result, alternative forms of relationships emerge that seek to resolve these problems and offer a better resolution strategy, such as open relationships, polyamory, or swinger relationships (between others).

These alternative relationship models that are increasingly present and visible are known as consensual non-monogamy (CNM). CNM is based on the concept of affective and/or sexual non-exclusivity. Sizemore and Olmstead (2017) [2] define CNM as a committed relationship in which the members agree to allow extradyadic romantic and/or sexual relationships. Different types of CNM relationships are usually established [3,4,5]. Polyamory refers to multiple long-term, non-exclusive romantic, loving, and/or sexual relationships and is understood as the ability to love several people at the same time and maintain stable relationships with all of them. Swinging (swinger relationships) denotes non-exclusive sexual relationships (not many romantic ones), especially between couples. This is an agreement between couples to have sexual relations with other people (usually with active or passive participation from both partners). Open relationships are generally understood as non-exclusive, long-term romantic relationships accompanied by other relationships that are primarily sexual, but they can also be romantic.

This means that individuals may have multiple relationships with different people at the same time, whether emotional and/or sexual, which can be occasional or regular over time.

Although CNM relationships are still a relatively understudied field, there has been an increase in research on the topic in recent years [1,3,4,5,6]. These studies report that approximately 20% of the population has experienced a CNM relationship at some point in their lifetime. Moreover, the prevalence of CNM experiences is higher among individuals who identify as gay, lesbian, or bisexual, with approximately one-third reporting engagement in CNM [4]. Additionally, it has been noted that sexual minorities, males, and young adults are more likely to have been in a CNM relationship or express a greater desire to engage in CNM compared to heterosexuals, females, and older adults, respectively [5]. In line with these findings, the authors of the Consensual Non-Monogamy Attitude Scale (CNAS) have shown that sexual minorities, including homo- and bisexual individuals, transgender individuals, and genderqueer individuals, hold more favorable attitudes toward CNM relationships compared to heterosexual individuals and cisgender individuals [7].

In a global context, attitudes toward polyamory vary widely depending on cultural, religious, and legal factors. In countries with cultures more focused on individualism, such as the United States or Canada, polyamory finds greater acceptance due to a focus on personal autonomy and freedom of choice. In contrast, in more conservative regions with a strong religious influence, such as the Middle East or parts of Asia, these relationships are often frowned upon or even condemned. However, since CNM relationships are gaining visibility, more studies addressing this topic are needed [2,4,5].

We could point to four substantial factors that concern every romantic relationship:

First, relationship satisfaction, or the so-called dyadic adjustment [8], refers to the quality of the relationship. Most of the previous literature did not find differences in overall relationship satisfaction between CNM people and monogamous individuals [4,6,9,10,11]. However, an exception was observed in Brooks et al.’s (2021) [12] study, in which differences were found between participants in monogamous and CNM relationships, not only in relationship satisfaction but also in commitment, intimacy, passion, love, and psychological well-being. In all these factors, CNM individuals reported higher levels.

Second, sexual desire, as defined by the author of the Sexual Desire Inventory (SDI), refers to the interest in sexual activity [13]. To date, no comparative studies have been conducted on sexual desire between monogamous and CNM practitioners. However, one could hypothesize that people in CNM relationships may have an increased interest in sexual activity due to a greater diversity of stimuli. Regarding sexual satisfaction, Conley et al. (2018) [9] demonstrated that monogamous people reported slightly lower sexual satisfaction and lower orgasm rates compared to CNM individuals. In contrast, Mitchell et al. (2020) [14] detected no significant differences in sexual satisfaction.

Third, jealousy is a response that arises when there is a real or perceived threat of losing an interpersonal relationship. Mogilski et al. (2019) [15] examined jealousy among individuals in monogamous romantic relationships and CNM relationships. In general, they observed that monogamous individuals experienced greater distress when imagining their partner being involved in an extradyadic relationship.

Finally, conflict resolution is crucial for the quality of the relationship and the general well-being of its members. Brooks et al. (2021) [12] examined conflict resolution styles between participants in monogamous and CNM relationships and found that individuals in CNM relationships tended to favor a positive approach to conflict with their partner, while monogamous participants used more withdrawal tactics. Currently, there is no other empirical evidence that has studied how different types of relationships resolve their conflicts.

The objective of this research is to compare these four substantial factors—relationship satisfaction (dyadic adjustment), dyadic sexual desire, jealousy, and conflict resolution—in both monogamous and CNM romantic relationships. Additionally, this study aims to contribute to the understanding of CNM relationships and provide knowledge on the destigmatization and normalization of diverse relationship types.

2. Materials and Methods

2.1. Participants

A total of 210 individuals participated in the study, with 143 identifying as female (68.1%), 64 as male (30.48%), and 3 identifying as “other” (1.43%).

This research study was carried out at the University of Oviedo in a small region in northern Spain; 83.3% of the participants came from different parts of Spain, 10% from Latin American countries, and 6.67% from European countries.

The age range of the participants was between 20 and 68 years, with a mean age of 32.43 (SD = 10.97). Among the participants, 162 were in a monogamous romantic relationship (77.14%), while 48 individuals were in a CNM romantic relationship (22.86%).

2.2. Measures

2.2.1. Short Version of the Dyadic Adjustment Scale (DAS-13)

The Dyadic Adjustment Scale-13 (DAS-13) is an abbreviated version of the Dyadic Adjustment Scale developed by Spanier (1976) [8] and adapted in Spanish by Santos-Iglesias et al. (2009) [16]. It is designed to measure the quality of couple relationships. The scale consists of 13 items that assess three dimensions: consensus, satisfaction, and cohesion. DAS-13 has demonstrated adequate psychometric properties for its application in the Spanish context, with an internal consistency reliability of 0.83 reported by Santos-Iglesias et al. (2009) [16]. However, in this study, the scale exhibited low reliability with a Cronbach’s alpha of 0.41.

2.2.2. Sexual Desire Inventory (SDI)

The Sexual Desire Inventory (SDI) [13] is an easily applicable instrument that was translated and validated in a Spanish sample by Ortega et al. (2006) [17]. The Spanish validation demonstrated good reliability, with Cronbach’s alpha coefficients of 0.87 for one factor and 0.88 for the other. Dyadic sexual desire is assessed using items 1 to 3, 7, and 8, which measure sexual desire with a partner, while items 4 to 6 and 9 measure sexual desire with an attractive person. By summing the scores of the nine items, a total score ranging from 0 to 70 is obtained. In the sample of this study, which used items 1 to 9 to measure dyadic sexual desire, a reliable score was obtained, with a Cronbach’s alpha of 0.85.

2.2.3. CECLA: Instrument for Evaluating Jealousy

The CECLA is an instrument designed to assess jealousy and was developed by Avendaño Prieto and Betancort Montesinos (2021) [18]. It comprises three factors that measure delusional jealousy, obsessive jealousy, and passionate jealousy. The subscales demonstrate satisfactory Cronbach’s alpha values: 0.89 for delusional jealousy, 0.87 for obsessive jealousy, and 0.84 for passionate jealousy. For this study, the three items with the highest factor loadings from each subscale were selected. Thus, the study included items 1, 2, and 5 for passionate jealousy; items 8, 9, and 10 for obsessive jealousy; and items 14, 17, and 18 for delusional jealousy. With these nine selected items, a reliability coefficient of 0.69 was demonstrated.

2.2.4. Conflict Resolution Styles Inventory (CRSI)

The Conflict Resolution Styles Inventory [19] was validated and adapted in Spanish by Bonache et al. (2016) [20], with a Cronbach’s alpha ranging from 0.78 to 0.87. This instrument measures conflict resolution skills and consists of a total of 13 items divided into three factors. The first factor assesses a positive approach to conflict and includes items 2, 5, 8, and 12. The remaining two factors represent non-constructive styles: involvement (items 1, 4, 7, and 11) and withdrawal (items 3, 6, 9, 10, and 13). The inventory is scored using the mean, and the total score ranges from 13 to 65. However, the Cronbach’s alpha for this test was low, measuring 0.4.

2.3. Procedure

This study employed a non-experimental, cross-sectional, and causal–comparative exploratory design.

The participants in this study (N = 210) were recruited through diffusion on social networks, specifically targeting groups of individuals who identify themselves as CNM. Additionally, notices were posted throughout the city of Oviedo, and snowball sampling was employed. Subjects had the opportunity to voluntarily respond to the questionnaire online. The data collection period spanned from 21 October 2022 to 13 November 2022.

2.4. Data Analysis

The data analysis used in this study consisted of four consecutive stages, as described below.

First, descriptive statistics were employed to examine the sociodemographic variables, and contingency tables were generated to associate the qualitative variables of interest, namely sex and the type of relationship, with the remaining qualitative variables (sex, sexual orientation, type of relationship, educational level, nationality, and religion). Cramer’s V statistic was used to establish a measure of the relationship between pairs of qualitative variables.

Next, a descriptive analysis was conducted by grouping the factors of the DAS-13, SDI, CECLA, and CRSI instruments according to the qualitative variables of sex (female and male) and type of relationship (monogamous and CNM). The results of this preliminary analysis, including the mean, standard deviation, and minimum scores obtained in each factor for each group, were recorded. Additionally, the symmetry and kurtosis of the factors were examined. The normality hypothesis was also tested using the Shapiro–Wilk test. The findings are summarized in

Table 1. Descriptive statistics of the factors of the Dyadic Adjustment Scale-13 and the Sexual Desire Inventory by sex and the type of relationship.

	DASF1		DASF2		DASF3		SDI
Sex/Relationship	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)
Female	7 a	24.81 (3.24)	11 a	15.43 (1.83)	6	12.27 (2.45)	4	41.08 (12.15)
Man	14	24.91 (3.14)	12	15.47 (1.83)	7	12.53 (2.41)	8	45.86 (11.86)
Monogamous	7 a	24.66 (3.31)	12	15.38 (1.71)	6	12.28 (2.44)	4	40.80 (11.93)
CNM	19	25.49 (2.70)	11	15.65 (2.15)	8	12.63 (2.38)	17	48.13 (11.36)

Note. ^a Kurtosis lower than 4.

and

Table 2. Descriptive statistics of the factors of the CECLA instrument for assessing jealousy and the Conflict Resolution Styles Inventory by sex and the type of relationship.

	CECLAF1		CECLAF2		CECLAF3		CRSIF1		CRSIF2		CRSIF3
Sex/Relationship	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)	Minimum	M (SD)
Female	3	7.41 (2.86)	3 ab	3.53 (1.26)	3 ab	3.51 (1.45)	2	4.12 (0.64)	1	1.91 (0.78)	1	1.95 (0.68)
Man	3	5.61 (2.26)	3 ab	3.33 (0.82)	3 ab	3.52 (1.52)	2.25	3.96 (0.79)	1	1.62 (0.61)	1	2.19 (0.69)
Monogamous	3	7.17 (2.83)	3 ab	3.51 (1.21)	3 ab	3.52 (1.51)	2	4.00 (0.70)	1	1.91 (0.77)	1	2.04 (0.67)
CNM	3	5.81 (2.47)	3 ab	3.29 (0.82)	3 ab	3.54 (1.41)	2.25	4.32 (0.60)	1	1.50 (0.53)	1	1.98 (0.74)

Note. ^a Kurtosis lower than 4. ^b Skewness lower than 4.

.

3. Results

The relationships between each factor and the qualitative variables of sex and type of relationship were further explored. Visual analysis was initially performed using stem-and-leaf plots to represent the factors of the DAS-13 and SDI, along with the two aforementioned qualitative variables. This representation created four subgroups (Figure 1). The same procedure was applied to the CECLA and CRSI factors, resulting in Figure 2. Subsequently, a group analysis of variance was conducted for each factor considering the qualitative variables of interest. Given that sex and relationship types were simplified into two distinct groups, the analysis of variance resulted in four subgroups: monogamous male, monogamous female, CNM male, and CNM female. The interactions between these subgroups were examined to identify any significant differences, as presented in

Table 3. Relationship with the quantitative variables (the factors from the four scales) and the sex (female and male) and type of relationship (monogamous and consensual non-monogamous).

Factors	MoF (n = 121; 58.5%)	MoM (n = 41; 19.8%)	CNMF (n = 22; 10.6%)	CNMM (n = 23; 11.1%)	ANOVA
DASF1	24.48 (3.35)	25.20 (3.20)	26.64 (1.73)	24.39 (3.03)	F = 3.238; p = 0.023; Eta = 0.046
DASF2	15.37 (1.72)	15.41 (1.72)	15.77 (2.39)	15.57 (2.06)	F = 0.15; p = 0.70; Eta = 0.00
DASF3	12.24 (2.45)	12.41 (2.43)	12.45 (2.52)	12.74 (2.42)	F = 0.02; p = 0.90; Eta = 0.00
SDI	39.43 (11.55)	44.85 (12.25)	50.18 (11.52)	47.65 (11.15)	F = 3.84; p = 0.05; Eta = 0.02
CECLAF1	7.62 (2.85)	5.83 (2.30)	6.27 (2.69)	5.22 (2.17)	F = 0.63; p = 0.43; Eta = 0.00
CECLAF2	3.60 (1.34)	3.24 (.62)	3.14 (0.47)	3.48 (1.08)	F = 3.12; p = 0.08; Eta = 0.02
CECLAF3	3.50 (1.49)	3.56 (1.57)	3.55 (1.26)	3.43 (1.47)	F = 0.11; p = 0.75; Eta = 0.00
CRSIF1	4.07(0.65)	3.80(0.82)	4.41 (0.51)	4.25(0.68)	F = 0.22; p = 0.64; Eta = 0.00
CRSIF2	2.01(0.78)	1.63(0.65)	1.38 (0.52)	1.59(0.56)	F = 5.54; p = 0.02; Eta = 0.03
CRSIF3	2.01(0.69)	2.14(0.61)	1.63 (0.53)	2.30(0.82)	F = 5.35; p = 0.02; Eta = 0.03

Note. The qualitative variables are as follows: MoF = monogamous female; MoM = monogamous male; CNMF = CNM female; CNMM = CNM male.

and

Table 4. Relationship with the quantitative variables (the factors of the four scales) and sex (female and male) and the type of relationship (monogamous and consensual non-monogamous). Post-hoc test.

	DMScheffe
Factors	MoF-MoM	MoF-CNMF	MoM-CNMM	CNMF-CNMM	F-M	Mo-CNM
DASF1	0.72	2.16	0.80	2.25
DASF2					0.04	0.28
DASF3					0.16	0.32
SDI	5.42	10.75	2.80	2.53
CECLAF1					1.80	1.43
CECLAF2					0.20	0.20
CECLAF3					0.01	0.03
CRSIF1					0.16	0.33
CRSIF2	0.37	0.63	0.05	0.21
CRSIF3	0.12	0.39	0.16	0.67

Note. The qualitative variables are as follows: MoF = monogamous female; MoM = monogamous male; CNMF = CNM female; CNMM = CNM male; F = female; M = male; Mo = monogamous; CNM = consensual non-monogamous.

. The analysis aimed to identify and assess the potential variations and disparities among the subgroups defined by the qualitative variables of sex and the type of relationship. In cases where the hypothesis of homogeneity of variance was not met, ANOVA was performed, adjusting the degrees of freedom using the Brown–Forsythe test. Mean comparisons were made using the Scheffé test. The significance level was set to 0.05.

The sample consists of 210 participants who were grouped into two relationship types: monogamy (n = 162) and CNM (n = 48).

Table 1 and Table 2 illustrate the relationship between the different factors of the four scales, with sex (female and male) on one hand and the type of relationship (monogamous and CNM) on the other. The minimum score obtained (minimum), mean (M), and standard deviation (SD) are displayed.

Figure 1 and Figure 2 describe the distribution of the factors of the DAS-13 and SDI (Figure 1) and of the factors of the CECLA and CRSI (Figure 2) for the four subgroups containing the sex and type of relationship.

Table 3 and Table 4 demonstrate the relationship between the quantitative variables (factors of each instrument) and the qualitative variables (sex and type of relationship). For this purpose, the mean score obtained in each factor, along with the standard deviation and ANOVA (Table 3) and the mean differences (Table 4), was utilized. Although robust tests were used for the inferential study, the results should be considered with caution due to the unbalanced groups and the incidental sample.

4. Discussion

The aim of this study was to compare monogamous and CNM relationship models with respect to variables such as relationship satisfaction, sexual desire, jealousy, and conflict resolution.

Regarding the sociodemographic data of the study participants, the majority were young females. This suggests that females and young people are more willing to fill out a questionnaire about their affective–sexual relationships and that there may be less taboo surrounding such discussions among them.

When examining the relationship type in relation to other qualitative variables, it is observed that the sample in this research primarily consists of monogamous females (74.7%; N = 121) compared to monogamous males (25.3%; N = 41). In polyamorous and other CNM relationships, there are slightly more females than males (54.5–58.3% and 41.7–45.5%, respectively). Only open relationships show a slightly higher representation of males (59.1%; N = 13) compared to females (40.9%; N = 9). It is noteworthy that individuals in monogamous relationships predominantly identify as heterosexual (80.6%; N = 129), while in CNM relationships, heterosexuality represents less than 50% of individuals, and there is a higher presence of bisexuality (40–64.3%) compared to bisexuality in monogamous relationships (15.6%). This result aligns with the findings of the studies by Haupert et al. (2017) [5] and Levine et al. (2018) [21], which detected a higher propensity for involvement in CNM relationships among homosexual and bisexual individuals.

The results obtained from the descriptive analysis of the groups with respect to the different factors of the four scales (and the type of relationship (monogamous and CNM) on one hand and sex (female and male) on the other) are described below and represented in Table 1 and Table 2. Upon initial observations and comparing the means, differences can be seen in the consensus (measured by the DASF1) between monogamous and CNM individuals. The mean score is higher for CNM individuals (25.49) compared to monogamous individuals (24.66). Looking at the means, it is evident that dyadic sexual desire is significantly higher in CNM individuals (48.13) and males (45.86) than in monogamous individuals (40.80) and females (41.08), respectively. Regarding jealousy, differences appear mainly in the dimension of passionate jealousy (CECLAF1). The mean scores for females (7.41) and monogamous individuals (7.17) are higher compared to males (5.61) and CNM individuals (5.81), respectively. At first glance, there do not appear to be significant differences in factors two and three of the DAS-13, which measure satisfaction and cohesion, and factors two and three of the CECLA, which assess obsessive and delusional jealousy. Similarly, the three factors of the CRSI (positive approach, involvement, and withdrawal) do not show substantial differences between the sexes or relationship types.

However, when further investigating the significant relationship and interactions of the four variables, changes occur. Thus, four new groups were obtained: monogamous female, CNM female, monogamous male, and CNM male. Additionally, Figure 1 and Figure 2 visually demonstrate the differences in factor responses among these four subgroups.

Furthermore, Table 3 and Table 4 present the relationship between the scales’ factors, sex, and relationship type. Upon studying the interaction between the four subgroups, it can be observed that there are significant differences in consensus (DASF1), dyadic sexual desire (SDI), conflict involvement (CRSIF2), and conflict withdrawal (CRSIF3). Regarding the other quantitative variables, no significant differences were found in the interaction of the four qualitative variables. However, significant differences were found in two additional pairwise variables: passionate jealousy (CECLAF1) and a positive approach to conflict (CRSIF1).

Regarding relationship satisfaction, as assessed using the DAS-13, the obtained data showed significant differences in the interaction of the four subgroups in consensus (DASF1). Females in CNM relationships demonstrated greater consensus within their relationships compared to monogamous females. Consensus refers to the ability, resources, and skills needed to reach agreements or find joint solutions to problems. In other words, the CNM females in this study appear to reach agreements and solve their problems somewhat more easily than monogamous females. It is possible that CNM females either acquire higher levels of reaching agreements or problem-solving skills as a consequence of being in a CNM relationship or possess these skills prior to entering such relationships. Most previous research found no differences in relationship satisfaction between CNM and monogamous individuals [4,6,9,10,11], which is also reflected in the present research when comparing the second and third factors of the DAS-13: satisfaction and cohesion. There were no significant differences observed in either the interaction of the four subgroups or the interaction between pairs. In this context, the satisfaction dimension (second factor of the DAS-13) refers to the level of well-being, happiness, and commitment within the couple, while the cohesion dimension (third factor of the DAS-13) measures the degree of involvement one partner has with the other, including interest, appreciation, seeking moments to share, etc. Thus, depending on the assessment instruments and their factors, it can be said that the results obtained align with those of previous studies.

However, Mogilski et al. (2017) [11] observed that monogamous individuals were less satisfied with the amount of conversation and openness compared to CNM subjects, which could align with the consensus of DAS-13 in this study. Maintaining multiple relationships simultaneously often necessitates more frequent agreements and increased organizational skills. Therefore, as a requirement or consequence of CNM relationships, it is conceivable that its practitioners possess more skills and resources for reaching agreements or finding joint solutions to problems, as observed in CNM females in this research. Nevertheless, it is interesting that these greater capacities were found solely in CNM females and not in CNM males.

The most striking and significant differences are seen in dyadic sexual desire. The SDI, which is used to measure sexual desire in this study, consists of only one factor, as it includes only the dyadic desire component. Studying the interaction between the four subgroups reveals clear and significant differences. CNM females (50.18) exhibit higher dyadic sexual desire than monogamous females (39.43). The mean difference is 10.75, the highest in the entire study. In other words, CNM females express the highest dyadic sexual desire (compared to the other three subgroups). The comparison of sexual desire between monogamous and CNM relationships has not been studied until today. However, the fact that CNM females have higher sexual desire than monogamous individuals can be possibly explained by the more frequent change in sexual partners and a more varied and perhaps more active sexual life. This deduction is based on what has been established: Passionate love decreases over the years in a long-term relationship [22]. It is assumed that with more changes at the sexual and/or emotional level in a CNM relationship, sexual desire remains higher. The fact that it is precisely CNM females who exhibit the most desire can be explained by the knowledge that sexual desire decreases more rapidly in females than in males [23], which may indicate that females experience more changes in their sexual desire when opening their relationship. On the other hand, the SDI measures the spontaneous sexual desire characteristic of initial relationships and not the reactive sexual desire more commonly found in long-term relationships and more prevalent in females than in males [24].

With respect to jealousy, no significant differences were found in the interaction between the four subgroups. Subsequently, when examining the groups pairwise, significant differences were observed in passionate jealousy (CECLAF1) between the two sexes. Females obtained higher scores than males, with a mean difference of 1.80. That is, according to the definition of passionate jealousy by Echeburúa and Fernández-Montalvo (2001) [25], females, in this case, are more likely to exhibit the emotional state of passionate jealousy that arises from the insecurity of losing their partner and can affect their clarity of mind and self-esteem, but at the same time, they are capable of recognizing their behavior as irrational. Additionally, the CECLA also evaluates obsessive jealousy (CECLAF2) and delusional jealousy (CECLAF3). Obsessive jealousy is understood as “thoughts, images, or mental impulses that manifest and intrude involuntarily and cause anxiety, to the point that the person is unable to reject thoughts related to infidelity”. Delusional jealousy refers to “false and irrefutable ideas that defy logical reasoning and make the person believe that their partner is unfaithful despite all evidence and arguments against it” [25]. No significant differences were found with respect to either obsessive or delusional jealousy neither in the interaction between the four subgroups nor in the pairwise comparisons, indicating that levels of obsessive and delusional jealousy are similar across all participants. Other studies investigating jealousy divided into the three delusional, obsessive, and passionate jealousy dimensions and comparing CNM and monogamous populations have not yet been conducted. However, it was observed that, in general, the distress of imagining one’s partner engaging in extradyadic relationships is greater for monogamous individuals than for CNM individuals, while CNM individuals imagine their partner in such situations more frequently [15]. Therefore, it is important to note that being in a CNM relationship does not eliminate the experience of jealousy but rather involves facing and dealing with it, perhaps more frequently and in a more assertive manner. To better understand the experience of jealousy in monogamous and CNM individuals, further research in this field is necessary.

Significant differences were observed in conflict resolution when examining the interaction between the four subgroups in the two non-constructive styles for coping with conflicts: conflict engagement (CRSIF2) and withdrawal (CRSIF3). Conflict engagement refers to the use of personal attacks and loss of control, while withdrawal involves refusing to discuss problems and disengaging from the partner [14]. Monogamous females showed the highest score in conflict engagement. Significant differences were found in this factor between monogamous females and monogamous males (0.37) and even more so between monogamous females and CNM females (0.63). In other words, monogamous females tend to engage in personal attacks and lose control more than monogamous males and CNM females. Withdrawal is the least-used technique by CNM females compared to the other three subgroups, showing significant differences compared to both monogamous and CNM males (0.51 and 0.67, respectively). In other words, males are more likely to refuse to discuss problems and disengage from their partners. Additionally, when comparing the groups pairwis2e, there were significant differences between monogamous and CNM individuals in positive problem-solving approaches. This type of conflict resolution is considered more adaptive and involves compromise and negotiation [19]. In this case, CNM individuals use this approach more than monogamous individuals (0.33).

In the same line, Brooks et al. (2021) [12] found, in their study, that CNM individuals approach conflict resolution with a more positive approach, while monogamous individuals tend to withdraw from conflicts. However, this area of study remains largely unexplored, and there is currently no other research on conflict resolution styles in CNM relationships. It is likely that CNM individuals face greater challenges due to societal norms being more aligned with traditional monogamous relationships.

The present study has some limitations, including the sample size of individuals in CNM relationships, the reliability of the DAS-13 and CRSI scales due to low Cronbach’s alpha values, and the lack of instruments specifically adapted for a CNM sample.

Regarding the sample size, although it would have been desirable to have greater participation, we do not know if it is actually too small, because there are no statistics on the representation of such particular characteristics in the population. Perhaps more concerning than having a low test power would be a distribution that is non-normal and a lack of homogeneity with respect to variances, which is exactly what happened, and this is possibly due to the difference in size between the groups; however, this issue is inherent in the difficulty of recruiting individuals in CNM. To address this problem, a decision was made to perform ANOVA, as it has been shown to be robust in the absence of normality [26]. In cases where the homogeneity of variances hypothesis was not met, ANOVA was performed, adjusting the degrees of freedom using the Brown–Forsythe test [27]. In this way, we estimate that the validity of the statistical conclusions is ensured. The results found in this research will make it possible for future studies to obtain more accurate calculations of the sample size. As for the low reliability observed, we estimate that this could be due to the small sample size and the variability in the population studied [28,29]. However, because these are validated scales used in other studies and given the careful data analysis conducted here, we believe that the results obtained with these scales are very informative.

The results highlight the need to create scales in order to more accurately assess the particularities of the population studied in this research.

5. Conclusions

In conclusion, the present investigation showed that CNM females exhibit higher consensus and therefore better dyadic adjustments, as well as higher dyadic sexual desires, compared to monogamous females. The levels of passionate, obsessive, and delusional jealousy are similar among practitioners of both monogamous and CNM relationships. Between the sexes, females exhibit higher levels of passionate jealousy than males. In terms of conflict resolution, CNM individuals employ a significantly more positive approach compared to monogamous individuals and make less use of conflict engagement techniques. CNM females are less likely to use withdrawal and engagement techniques. Additionally, CNM males tend to withdraw more from conflicts compared to CNM females. The obtained results contribute to the overall understanding of differences and similarities in relational models between monogamy and CNM among females and males in Spain. Collectively, the results support past findings of the overall health and functionality of CNM relationships, which deviates from the mono-normative assumptions of our society. The importance of further research into different relationship models is emphasized, as promoting such research is also necessary in professional and mental health contexts.

Furthermore, it would be optimal to increase the overall sample size to obtain a more evenly distributed range of ages, educational levels, nationalities, sexual orientations, and identities. The validation and development of questionnaires better adapted to relationships other than monogamy should be considered, as most of the questionnaires currently available are specifically aimed at heteronormative couples. This will enable clinicians and therapists to provide the best possible assistance and therapy that aligns with each individual case.