Prevention and Risk: Treatment With a New Emphasis on Relationships

Inclusion Criteria: * 18 to 29 years of age (inclusive); * Main partner must be aged 18 or older. * Must be in a main partner relationship with another male (duration ≥ 1 months); * HIV-negative serostatus (confirmed by rapid test); * Recent (past 30 day) use of at least one of the substances identified as most commonly used by YMSM (marijuana, cocaine, methamphetamine, heroin or other opiates, MDMA, psychedelics, GHB, and/or ketamine); * Sexual behavior meeting CDC criteria for PrEP candidacy (TRB with a casual partner in the past 30 days or TRB with a non-monogamous or serodiscordant main partner). * Participants must reside in the NYC metro area * Ability to communicate in English Exclusion Criteria: * Unstable, serious psychiatric symptoms (assessed by the Psychotic Disorder subsection of the Structured Clinical Interview for DSM-IV); * Current suicidal/homicidal ideation; * Evidence of gross cognitive impairment (a score of \<24 on the mini-mental state examination) * A history of severe physical or sexual Intimate Partner Violence (IPV) victimization in the current relationship in which participants report not currently feeling "safe" in their relationship and/or coerced to participate in the study.