Objective To explore the differences in sexual risk behaviour between men who have sex with men (MSM) with steady partners versus casual partner(s) in the gay community.

Methods This online cross-sectional convenience-sampling study assessed MSM practices, their knowledge and their motivation regarding safe sex. Participants not knowing their HIV status or who performed insertive or receptive unprotected anal intercourse (UAI) or with a sex partner whose HIV status was unknown or discordant were considered ‘at-risk’.

Results Of all 2569 participants who completed the questionnaire, 907/2569 (35.3%) had a steady partner, and 896/2569 (34.9%) had a casual partner(s) in the past 6 months. 262/907 (28.9%) with steady partners and 248/896 (27.7%) with casual partners demonstrated at-risk sexual behaviour. Of all participants with steady partners, 108/907 (11.9%) performed UAI with their partner without undergoing mutual HIV testing. Of all participants with steady partners, 476/907 (52.5%) had a concurrent casual partner, and 144/476 (30.3%) performed UAI with both the steady and the casual partner. Of all participants with steady partners, 775/907 (85.4%) negotiated the possibility of sex outside their relationship with their main partner. The length of the steady relationship correlated with the number of concurrent casual partners.

Conclusions At-risk sexual behaviour was associated with insufficient negotiation skills, difficulties in condom use and a general risk-taking profile. Health educators should encourage MSM with steady partners to perform HIV testing before practising UAI, to improve their negotiation skills during the contact and to support open discussions with regard to sexual contact besides the steady relationship, as it may not be monogamous.