Why do men and women seek to form and maintain romantic relationships? Although men and women desire committed romantic partnerships to a similar degree, men have a stronger desire for sex than women do (Jackson & Kirkpatrick, Reference Jackson and Kirkpatrick2007; Peters, Maner, & Meltzer, Reference Peters, Maner and Meltzer2025). Compared to women, men think about sex more, have more sexual fantasies, experience greater sexual desire, initiate sex more often, and are less willing to forgo sex (Baumeister, Catanese & Vohs, Reference Baumeister, Catanese and Vohs2001). Given that most sex occurs in the context of long-term relationships (Wellings et al., Reference Wellings, Collumbien, Slaymaker, Singh, Hodges, Patel and Bajos2006), relationships provide consistent access to a sexual partner. We propose that men’s desire for consistent sex plays a substantial role in their initiation of, desire to maintain, and lower likelihood of dissolving romantic relationships, as well as their greater distress following dissolution.

Compared to partnered individuals, single individuals report less satisfaction with their sex lives and lower sexual frequency (Kislev, Reference Kislev2020). Moreover, single individuals who report less sexual satisfaction also report a stronger desire for a partner, a stronger desire to marry, and are less satisfied with singlehood (Park, Impett, & MacDonald, Reference Park, Impett and MacDonald2021). Thus, the desire for sex is one key reason that people enter relationships. Given men’s high sexual motivation, men likely strive harder than women to find a relationship partner to fulfill their sexual needs.

Supporting this perspective, men tend to overperceive women’s sexual interest (Haselton & Buss, Reference Haselton and Buss2000), which motivates approach behaviors during initial encounters such as speed dates (Perilloux, Easton, & Buss, Reference Perilloux, Easton and Buss2012). Men also report experiencing “love” at first sight more often than women do. Feelings of romantic love are unlikely to develop so quickly; thus, men’s tendency to experience love at first sight likely reflects sexual attraction (Zsok et al., Reference Zsok, Haucke, De Wit and Barelds2017). Men also typically confess love, commitment, and affection earlier than women do (Ackerman, Griskevicius, & Li, Reference Ackerman, Griskevicius and Li2011), but those confessions may represent attempts to secure sexual access. In one study, 71% of men (versus 39% of women) reported intentionally deceiving a partner about their romantic feelings to secure sex (Buss, Reference Buss2016). Thus, men may strive more strongly to initiate relationships, in part, to gain sexual access.

Once in a romantic relationship, men can benefit further from maintaining that relationship, ensuring consistent sexual access over time. Indeed, people rate faithfulness and a strong sex life as the two most important factors for a successful marriage, surpassing factors such as adequate income and shared interests (Taylor, Funk, & Clark, Reference Taylor, Funk and Clark2007). Given men’s stronger sexual motivation, men may experience greater relational benefits than women from the consistent sexual need fulfillment a relationship provides. Supporting this, the association between sexual satisfaction and relationship satisfaction is stronger for men than women (Impett, Muise, & Peragine, Reference Impett, Muise, Peragine, Tolman, Diamond, Bauermeister, George, Pfaus and Ward2014), and changes in sexual frequency are associated with changes in relationship satisfaction for men but not for women (McNulty & Fisher, Reference McNulty and Fisher2008).

Men’s lower likelihood of initiating relationship dissolution may partly reflect anticipated loss of sexual access, as well as the benefits (e.g., psychological, health) of engaging in regular sex. This implies that if the relationship lacks regular or satisfying sexual activity, men may be more rather than less willing to terminate the relationship. Indeed, lower sexual frequency, more sexual problems, and the belief that one’s sex life will not suffer or improve following breakup are associated with dissolution risk for men and women (Sprecher, Reference Sprecher1994; Yabiku & Gager, Reference Yabiku and Gager2009).

Relationship dissolution signifies the loss of sexual access, and for that reason, may be especially distressing for men. Indeed, men report more sexual frustration post-breakup than women do (DeLecce & Weisfeld, Reference DeLecce and Weisfeld2016). To restore sexual access, men may rekindle sexual relationships with ex-partners. In one study, approximately 27% of participants reported recent sex with an ex-partner (Halpern-Meekin et al., Reference Halpern-Meekin, Manning, Giordano and Longmore2013). Compared to women, men report greater receptivity to sex with an ex-partner regardless of who initiated the breakup (Moran, Wade, & Murray, Reference Moran, Wade and Murray2020). Men also view their ex-partners more favorably than women do, and this is explained not only by social support from the ex-partner but also by men’s more permissive sexual attitudes (Athenstaedt et al., Reference Athenstaedt, Brohmer, Simpson, Müller, Schindling, Bacik and Van Lange2020). Moreover, men report that staying friends with an ex-partner is more motivated by maintaining sexual access than women do. Of note, no sex differences emerged in emotional or support reasons for ex-partner friendship (Mogilski & Welling, Reference Mogilski and Welling2017). Finally, men are more likely to report having sex with an ex-partner to satisfy their sexual needs than women are; no sex differences emerged in emotional reasons for sex with an ex-partner (Moran et al., Reference Moran, Wade and Murray2020). Thus, men may be more distressed post-breakup than women due to a loss of sexual contact and thus engage in behaviors to restore that contact.

If sex differences in sexual motivation help explain why romantic relationships matter more to men than to women, individual differences should moderate this pattern. For instance, because those with more (versus less) unrestricted sociosexual orientations tend to pursue sex without emotional commitment (Simpson & Gangestad, Reference Simpson and Gangestad1991), sexual motivation may drive pursuit and maintenance of relationships more strongly for unrestricted men than restricted men. Supporting this, high sexual frequency and sexual satisfaction buffer unrestricted individuals from relationship dissatisfaction (French, Altgelt, & Meltzer, Reference French, Altgelt and Meltzer2019), and they report more desire for and actual sex with an ex-partner (Moran et al., Reference Moran, Burch, Wade and Murray2024).

Sexual motivation should also be a stronger mechanism underlying relationship formation and maintenance among younger men (i.e., when sex is most strongly tied to reproductive success), while emotional support may be the primary mechanism operating among older men. Indeed, men and women report less sexual desire as they age (DeLamater & Sill, Reference DeLamater and Sill2005), while reporting increases in support from close relationships (Schnittker, Reference Schnittker2007). Moreover, ageing involves a motivational shift away from mate-seeking and toward mate-retention, positive emotional experiences, and close support networks (Carstensen, Mikels, & Mather, Reference Carstensen, Mikels and Mather2006; Neel et al., Reference Neel, Kenrick, White and Neuberg2016).

Future research would benefit from systematically teasing apart the relative contributions of emotional support and sexual motivation mechanisms that underlie sex differences in relationship importance.