Marriage is a social institution in many cultures, under which two (or more) individuals create a familial and legal bond, often forming the basis of a family unit.
One Human marriage that was plagued by discord was the union between Michael and Patricia Bickley. The pair were married and cohabited in quarters aboard the Federation starship USS Enterprise-D where they served Starfleet as the backup flight controller and operations manager, respectively. The couple were known to have great affection for each other, passionately kissing when given occasion, such as under the mistletoe at the Enterprise Christmas party, but normal interaction between the two frequently consisted of unanticipated insults and petty bickering. Captain Jean-Luc Picard had to caution the pair to keep their personal interplay to a minimum when an argument interfered with their duty during an emergency situation that required them to serve side-by-side on the bridge. (TNG comics: "... Where No One Has Gone Before!", "Spirit in the Sky!")