Recent scholarship in the wake of Obergefell v Hodges has begun to question the monopoly of monogamous conceptions of marriage; this year has seen both a special issue of the Emory Law Review devoted to the legal status of plural marriage and the publication of Stephen Macedo’s Just Married. Critics point to the historically discriminatory antecedent forms of polygamy; advocates point to liberal commitments to individual autonomy. Both groups share a focus on toleration, presuming that plural marriages represents an other compared with monogamous marriage. I argue against this view. Rather than understanding plural marriage as different from monogamous marriage, we should instead recognize the fundamental continuity between monogamous and plural marriages. This continuity is revealed once we recognize sexual interactions as a subset of social interactions generally; the practice of negotiating social boundaries is one in which every couple engages. Thus, all marriages are simultaneously open and closed, and all couples must learn to negotiate the complex ways in which their marriage intersects and interacts with a variety of other persons: family members, friends, colleagues, and (in the case of plural marriages) lovers. This reunderstanding shifts scholarly focus away from questions of toleration, and towards a richer understanding of what marriage is and can be.