mate

Synonyms: acquaintance alter ego analog assistant associate bedmate bride buddy chum classmate cohort colleague companion compeer complement comrade concomitant consort coordinate counterpart coworker crony double duplicate familiar friend groom helper helpmate intimate match pal peer playmate reciprocal roommate schoolmate sidekick spouse twin

Synonyms: cohabit copulate couple crossbreed generate join land match merge pair procreate serve tie tie the knot wed yoke

Antonyms: abstain uncouple