mo·nog·a·my 
(mə-nŏgə-mē)
(mə-nŏgə-mē)n.
1. The practice or condition of having a single sexual partner during a period of time.
2.
a. The practice or condition of being married to only one person at a time.
b. The practice of marrying only once in a lifetime.
3. Zoology The condition of having only one mate during a breeding season or during the breeding life of a pair.
mo·noga·mist n.
mo·noga·mous adj.
mo·noga·mous·ly adv.