This chapter examines the implications of the extension of marriage to same-sex couples, focussing particularly on sex and sexuality. The Thirty-fourth Amendment to the Constitution of Ireland and the Marriage Act 2015 removed the former barriers to the marriage of same-sex couples in the Republic of Ireland. Since November 2015, same-sex couples may marry on the same basis as opposite-sex couples. Nonetheless, the Marriage Act is silent on the topics of adultery and consummation, both of which involve engaging in heterosexual sexual intercourse. Likewise, precedent in Ireland suggests that an opposite-sex marriage involving a gay spouse may be voidable under a ground of annulment relating to incapacity to form and sustain a normal marital relationship. These laws and precedents reflect the fundamentally heteronormative underpinnings of marriage, and suggest that some further interrogation of the sexual dimensions of marriage law is required in order to address the new reality of equal marriage.