Same-sex marriage is a widely debated issue, including in Australia. This study used an online anonymous survey, with free-text responses, to investigate romantic and sexual relationships among Australian gay and bisexual men. We sought to identify what proportion of such men intended to marry their primary regular partner if marriage was made legally available to same-sex couples in Australia, as well as factors associated with intention or non-intention to marry. Most men in the sample did not intend to marry their primary regular partner. Even among men who considered themselves to be in a 'relationship' with their primary regular partner, less than half intended to marry him. However, many men who would not marry their current primary regular partner agreed that same-sex marriage should be available for gay and bisexual men in Australia. Reasons for intention to marry included a desire for social and legal equality, and ideas about marriage as a rite of passage, an expression of love and the most valued form of relationship in Australia. Those who did not intend to marry their primary regular partner offered a number of reasons, including that the nature of their relationship was incompatible with marriage, and reported a critical position towards marriage as a heteronormative institution.