Interdependence and Sexual Health: Relationship factors associated with sexual behavior among sexual minority males in non-monogamous relationships who use drugs.

Sexual HIV transmission risk among sexual minority men (SMM) in relationships has been the focus of considerable research informed by interdependence theory. We tested a hypothesized model that situated condomless anal sex (CAS) with casual and main partners in the context of cannabis and illicit drug use, joint coping to reduce HIV risk, and relationship quality. A sample of 192 cisgender SMM aged 18 to 35 completed survey measures and a 30-day timeline follow-back interview of drug use and sexual behavior. Multi-level path model results indicated participants were more likely to have CAS with casual partners on days they had CAS with their main partner during group sex but less likely on days they had CAS with their main partner one-on-one. Illicit drug use was indirectly associated with CAS with casual partners through a pathway involving CAS with main partners during group sex and directly associated with CAS with casual partners among those SMM on PrEP. Both CAS with casual partners and with main partners one-on-one were more likely on days participants used cannabis. At the person-level, relationship costs were negatively associated with joint coping; meanwhile, perceptions that the relationship approximated an ideal were positively associated with joint coping. In turn, joint coping was negatively associated with the likelihood of CAS with casual partners. Relationship investment was positively associated with main partner CAS during group sex. Results underscore the importance of developing sexual health interventions for SMM in relationships that enhance relationship quality, catalyze joint coping, and address substance use.