Alcohol and other drug use, gender power inequities and violence are key contributors to sexual risks for HIV among South African men and women. Little is known about the intersection between these sex-risk behaviours among couples in established heterosexual relationships. We conducted 10 focus-group discussions with men and women in relationships of 1 year or longer recruited from shebeens (informal taverns) in Cape Town, South Africa. Participants described: high levels of alcohol consumption at shebeens; low levels of condom use with main and casual sex partners; gender roles disfavouring women's condom negotiating power that also promoted economic dependency on male partners; men often spending a portion of the household income on alcohol and other drugs and sex with others in shebeens; loss of household income driving women to trade sex to provide for their families; and sexual violence and the exploitation of women occurring in shebeens. Findings highlight how the social contexts of alcohol and other drug use, gender inequitable norms and gender violence promote HIV risk within established heterosexual relationships in South African communities. Evidence of this kind should inform the design of HIV-risk-reduction interventions tailored to heterosexual couples who drink alcohol in shebeens.