Multilateral marriage is a term for a relationship where three or more people consider themselves to be married to the others in the relationship group. Group marriage researchers Larry and Joan Constantine coined the term in their 1973 book Group Marriage: A Study of Contemporary Multilateral Marriage.
Today, multilateral marriage is considered a type of group marriage. However, the Constantines created the term as an alternative to group marriage, which at the time referred to a four-person marriage between two men and two women. The Constantines’ idea of multilateral marriage could include a marriage group of any size, made up of people of any gender and sexual orientation. They dubbed the people in these types of marriages cohusbands and cowives.
More About Multilateral Marriage
Marrying multiple people is illegal in most parts of the world. However, the people in a multilateral marriage consider themselves to be married in their hearts, even if their marriage is not recognized by law. Many people in multilateral marriages hold commitment ceremonies, which resemble marriage ceremonies, in order to formally sanction their relationships.
Despite their lack of legal recognition, the people in a multilateral marriage typically behave similarly to other married couples. They most commonly live together and share household chores and finances, as well as raise children together. People within multilateral marriages often have more defined household roles than traditional married dyads in order to ensure they are not in competition with one another. While the people within a multilateral marriage may not all love one another equally, this does not seem to matter as much as their commitment to making the marriage work.