Concubinage is the state of a couple living together with no obligation created by vows, legal state of matrimony, or religious ceremony. In the Western world, this term has become antiquated and has been replaced by the terms Common law marriage or de facto marriage. Consequently the term is generally used to signify an outdated relationship model where the male is the dominant partner, socially and economically. In this model the male may also have one or more wives in addition to the concubine.
Concubinage was frequently voluntary as it provided a measure of economic security for the woman involved in the relationship. When involuntary, "servile concubinage" involves the chattel slavery of one member of the relationship, most typically the woman.