Monogamy is the practice of forming romantic relationships with only one partner at a time, as opposed to having multiple partners at once. A monogamous relationship is a relationship where two people date and have sex with each other exclusively, and they don’t share this type of connection with anyone else outside the couple. There is romantic, sexual, and emotional exclusivity between them.
Today, monogamy is the most mainstream approach to relationships across many societies, though it’s by no means universal. Various cultures across the world practice polygamy (marriage between more than two people), and historically the majority of preindustrial societies engaged in polygamy of some sort, typically in the form of polygyny (two or more women sharing a husband). Monogamy is also a rarity among other mammals, with just 3% of mammals engaging in monogamy according to one recent analysis.
“Most of us have learned that monogamy is the ‘normal’ or even the ‘traditional’ relationship style and that non-monogamy is an alternative, when in fact non-monogamous relationships like polyandry, polygyny, [and] polygamy have been around for centuries,” Jayda Shuavarnnasri, M.A, a sex and love educator who teaches about non-monogamy and supports people exploring non-monogamous relationships, tells mbg.
While there are many theories as to why human societies transitioned from primarily polygamous to primarily monogamous, what we do know is that monogamy as the social norm is a relatively recent development in the scope of human history.
That said, in many societies today, monogamy is often treated as the default way of being in relationships. The common understanding of the way relationships form—from initial meeting, to becoming exclusive, to confessions of love, to moving in together, to eventually getting married and having kids—are all tied to the concept of monogamy, as are popular conceptions of romantic love such as finding “the one” or meeting “my other half.”