What is the X in X-mas?
monogamy mo·nog·a·my (mə-nŏg'ə-mē)
The practice or condition of being married to only one person at a time.
The condition of having only one mate.
the custom that allows a person to be legally married to only one spouse at one time. Appearing in two general forms, monogamy may imply a lifelong contract between two individuals that may be broken only under penalty-as prevails in the Roman Catholic and Hindu prescriptions for marriage-or it may imply that persons are required to be monogamous but may change spouses repeatedly, a practice sometimes called serial monogamy.