co·hab·it 
(kō-hăbĭt)
(kō-hăbĭt)intr.v. co·hab·it·ed, co·hab·it·ing, co·hab·its
1. To live together in a sexual relationship, especially when not legally married.
2. To coexist, as animals of different species.
[Late Latin cohabitāre : Latin co-, co- + Latin habitāre, to dwell; see INHABIT.]
co·habi·tant, co·habit·er n.
co·hab′i·tation n.
co·hab′i·tation·al adj.