Groommate
(n.) a man who is married to a woman, for seemingly no sexual reasons. His only use to his wife is purely for reasons of social and financial convenience.
"Ted complained that he and his wife hadn't had sex all last month. When will he realize that he's just a groommate at this point?"
groommate
A groomsman who also has been the groom's roommate.
Kevin is upgrading from roommate to groommate status.
groommate
A male friend (or roommate) of yours who is getting married.
Mike and I aren't really friends, so much as groommates.