Couples, Sexual Health, and Group Sexual Encounters

"Studies have examined sexual agreements and misunderstandings, commitment and sexual decision making, as well as drug use and sexual risk taking. A curious detail is evident in these studies. Condomless sex with a relationship partner and condomless sex with outside partners (any partner other than the primary relationship partner) tend to be positively correlated with one another, regardless of how these behaviors are assessed."

"Those who have condomless sex with outside partners (at least once in the past 30 days) are more likely to have condomless sex with their relationship partner (Starks et al., 2015). Those who have condomless sex with outside partners more often also have condomless sex with their relationship partner (Starks et al., 2021). One study even observed that condomless sex with outside partners was significantly more likely on the days that condomless sex with a relationship partner also occurs (Starks et al., 2021)."

"This correspondence has health implications. If either relationship partner contracts HIV or another STI during sex with an outside partner, they could subsequently expose the other partner during sex together. Estimates suggest that between one-third and two-thirds of new HIV infections among sexual minority men is transmitted sexually between relationship partners (Goodreau et al., 2012; Sullivan et al., 2009). Our recent study (Starks et al., 2025), published in The Journal of Sex Research, examined this association in more detail."

Multiple studies consistently find a positive correlation between condomless sex with primary relationship partners and condomless sex with outside partners among sexual minority men. Condomless sex with outside partners predicts greater likelihood and frequency of condomless sex with the primary partner, and daily-level data show concurrent occurrences. If a partner acquires HIV or another STI during outside-partner sex, the primary partner is at direct risk through subsequent condomless sex. New data indicate that group sexual encounters involving both relationship and casual partners, rather than sequential separate encounters, help explain this correlation. Coordinated prevention, testing, and treatment across partners can reduce couple-level sexual health risk.

Read at Psychology Today