This study utilizes a randomized controlled trial design to evaluate the efficacy of couples motivational interviewing (MI) to reduce the frequency and severity of illicit drug use and frequency of HIV transmission risk behavior (TRB). Participants are randomized to one of two conditions: couples MI or standard couples HIV testing and counseling (CHTC).

Inclusion Criteria:

• Have a main partner who is another cisgender male and have been in a relationship for 3 month or longer
• Index participant must be between 18 and 55; Main partner can be any age 18 and older
• One participant must be HIV negative (as confirmed by rapid test)
• One participant must have used at least 1 drug in the past 30 days (cocaine/crack, opiates, misuse of prescription medication, stimulants, psychedelics, ecstasy, ketamine, GHB, amyl nitrite)
• Index participant must have engaged in TRB in the past 30 days- Defined as CAS with a casual partner, or a serodiscordant or non-monogamous main partner
• Live in the United States
• Speak and read English

Exclusion Criteria

• Any signs of serious mental illness or cognitive deficit
• Current suicidal/homicidal ideations
• History of IPV with their main partner and safety concerns in the current relationship.

Both partners in the couple must identify as male.