roommate

noun

1. A person with whom one shares a room, as in a dormitory, barracks, rooming house, or apartment.
2. (Australia, Canada, New-Zealand, Philippines, US)A person sharing the same home albeit not the same room (but generally not a family member or spouse).

   “I live with Marsha. We’re roommates.”

3. (humorous, ironic)A same-sex significant other with whom one lives; a coinhabitant in a non-heterosexual relationship.