RESUMO
Understanding the sexual relationships of young women is critical for preventing HIV infections. This study aimed to describe the sexual behaviour of partners, comparing the accuracy of sexual health knowledge between partners. The study took place in 2017 in KwaZulu-Natal, South Africa. Purposive sampling was used to select 18-27-year-old sexually active women. Consenting female participants completed a structured and semi-structured interview, while consenting male sexual partners identified through the female participant completed a structured questionnaire on sexual health information. Using a reflexive inductive approach and thematic analysis, we identified key discrepancies in the assumptions partners make about each other's sexual health information. Twenty-three sexual dyads were identified and four key discrepancies were identified: Age: partners either over or underestimated the age of their partners, HIV status: where partners were unaware of, or incorrectly assumed their partner's status, Lack of awareness of partner's concurrent relationships and more general knowledge of the partner's sexual health behaviours. Discussions about sexual health are mediated by relationship length, type of partner, power and perceived fidelity. While it is possible to undertake dyadic level research, ethical tensions remain. Sex-positive and egalitarian sexual health interventions that target the individual, as well as the sexual relationship, are needed.