Men who have sex with men (MSM) continue to be disproportionately impacted by STIs and HIV. In addition to traditional risk factors, increasing attention has been given to the potential role of affective components of a sexual encounter, including mood state. To date, no study has described sexual behaviors engaged in by those who report being in love (or not) during a given sexual event. Internet-based survey data were collected from 24,787 gay and bisexual men who were members of online websites facilitating social or sexual interactions with other men. Measures included sociodemographics, recent sexual behavior history, sexual event characteristics, and perceptions of "love" with men's most recent male sexual partner. Participants' mean age was 39.2 years; ethnicities included white (84.6 %), Latino (6.4 %), and African American (3.6 %). Nearly all men (91 %) were matched by presence (I love him/he loves me), absence (I don't love him/he doesn't love me), or uncertainty (I don't know if I do/I don't know if he does) of love with their most recent sexual partner. Men who reported love for their partner and believed their partner loved them were significantly more likely to have engaged in behaviors such as cuddling and kissing on the mouth. Differences were also seen in regard to love and men's reports of anal intercourse and oral sex. Findings highlight differences in sexual behaviors based on perceptions of love and suggest the need to further explore how these differences influence sexual health.