roommate

noun3

1. •
   a person who shares a room with someone, for example at school or in the army
2. •
   (US, Australia) 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. — 2016
3. •
   (humorous, euphemistic) A same-sex significant other with whom one lives; a coinhabitant in a non-heterosexual relationship.