Monogamy and Nonmonogamy: Evolutionary Considerations and Treatment Challenges

Romantic relationship configurations and their correlates among LGBTQ+ persons: A latent class analysis

Research comparing monogamous and non-monogamous relationships on well-being indicators across diverse populations have yielded inconsistent findings. The present study investigates sociodemographic characteristics, as well as personal and relational outcomes, across different relationship configurations. Data were drawn from an online community-based sample of 1,528 LGBTQ+ persons aged 18 years and older in Quebec, Canada. A latent class analysis was performed based on legal relationship status, relationship agreement, cohabitation status, and the seeking of extradyadic sexual and romantic partners on the internet. Class differences on sociodemographic characteristics and well-being and relationship quality indicators were examined. A five-class solution best fit the data, highlighting five distinct relationship configurations: Formalized monogamy (59%), Free monogamy (20%), Formalized open relationship (11%), Monogamous considering alternatives (7%) and Free consensual non-monogamies (3%). Cisgender women were more likely to engage in monogamous relationships than cisgender men, who were overrepresented in open relationships. Lower levels of perceived partner support were observed in both free monogamous and consensually non-monogamous relationships, the latter of which also showed lower levels of well-being. Consensual non-monogamy researchers exploring relationship outcomes should examine relationship facets that go beyond relationship structure or agreement. Variations in monogamies and non-monogamies, both consensual and non-consensual, may be present within each broad relationship configuration, as reflected in different personal and relational needs, which can then translate to better or poorer outcomes.

Differences in Motivation to Engage in Sexual Activity Between People in Monogamous and Non-monogamous Committed Relationships

This study compared motivations to engage in sex between monogamous and non-monogamous respondents (n = 1,238, out of which 641 monogamous and 596 non-monogamous respondents; women-47.4%, men-50.9%, other gender-1.7%; age: M = 27.78 years, SD = 7.53, range = 18-62). The research aim was to identify whether there are differences in self-reported reasons to engage in sexual activity between these two groups. Presented with 17 reasons to engage in sexual activity, the respondents rated the frequency with which they engage in sex for each reason. While both monogamous and non-monogamous respondents reported to engage in sex with the same frequency for the reasons of sexual release and physical desirability of a partner, the research uncovered that non-monogamous respondents engage in sex significantly more often to seek new experiences, to boost self-esteem, to guard their mate, to have a specific kind of sex (such as anal, kink, or fetish) or to experience the thrill of the forbidden. Non-monogamous respondents reported higher frequency to engage in sex for most reasons overall. The study also revealed that there are differences in reasons to engage in sex among men and women, some of the differences are related to the relationship status (monogamous or non-monogamous), while others are universal for men or women irrespective of their monogamy status.

Life History and Multi-Partner Mating: A Novel Explanation for Moral Stigma Against Consensual Non-monogamy

Life history theory (LHT) predicts that individuals vary in their sexual, reproductive, parental, familial, and social behavior according to the physical and social challenges imposed upon them throughout development. LHT provides a framework for understanding why non-monogamy may be the target of significant moral condemnation: individuals who habitually form multiple romantic or sexual partnerships may pursue riskier, more competitive interpersonal strategies that strain social cooperation. We compared several indices of life history (i.e., the Mini-K, the High-K Strategy Scale, pubertal timing, sociosexuality, disease avoidance, and risk-taking) between individuals practicing monogamous and consensually non-monogamous (CNM) romantic relationships. Across several measures, CNM individuals reported a faster life history strategy than monogamous individuals, and women in CNM relationships reported earlier pubertal development. CNM individuals also reported more social and ethical risk-taking, less aversion to germs, and greater interest in short-term mating (and less interest in long-term mating) than monogamous individuals. From these data, we discuss a model to explain how moral stigma toward non-monogamy evolved and how these attitudes may be mismatched to the modern environment. Specifically, we argue that the culture of sexual ethics that pervades contemporary CNM communities (e.g., polyamory, swinging) may attenuate risky interpersonal behaviors (e.g., violent intrasexual competition, retributive jealousy, partner/child abandonment, disease transmission) that are relatively more common among those who pursue multi-partner mating.

Jealousy, Consent, and Compersion Within Monogamous and Consensually Non-Monogamous Romantic Relationships

Evolutionary psychological research has studied romantic jealousy extensively within monogamous relationships, but has largely ignored jealousy among partners who mutually consent to forming extra-pair relationships (i.e., consensual non-monogamy; CNM). We examined monogamous (n = 529) and CNM (n = 159) individuals' reactions to imagining their romantic partner(s)'s extra-pair involvement. For each romantic partner, men and women completed measures of relationship jealousy and reacted to scenarios of their partner's extra-pair emotional and sexual involvement. Scenarios prompted participants to indicate which type of involvement would be more distressing and more enjoyable. They also described whether or not participants had consented to their partner's extradyadic relationship. Monogamous men were more distressed by a partner's extradyadic sexual versus emotional involvement (and a partner's emotional involvement was more enjoyable) whether the scenario was consensual or not. Monogamous women were more distressed by a partner's emotional versus sexual involvement (and a partner's sexual involvement was more enjoyable) for consensual, but not non-consensual, scenarios. There were no gender differences among CNM participants. Monogamous individuals reported greater emotional distress toward a partner's imagined extradyadic involvement, whereas CNM individuals reported thinking about their partner's extra-pair relationships more frequently. Monogamous (vs. CNM) individuals reported greater confidence that their partner would never cheat on them (i.e., enter another relationship without their consent), and CNM participants were more confident that their primary versus secondary partner would never cheat, although this effect was stronger among CNM women. Moreover, CNM participants rated that it was more important that their primary versus secondary partner did not cheat, and reported greater distress imagining that their primary versus secondary partner had cheated. Women in CNM relationships rated it more important that their partner did not cheat sexually than emotionally. Finally, we replicated previous research showing that monogamous individuals mate guard more than CNM individuals, who mate guard their primary versus secondary partner more frequently. Future directions for developing evolutionary and romantic relationship research on CNM are discussed.