[cout]

My wife and I still call each other boyfriend/girlfriend, but we are old fashioned. We like it because we are an dating (each other), even though we are married.

One argument in favor of using partner is that boyfriend/girlfriend is ambiguous. My wife often refers to her close female friends as "my girlfriend", even though they are clearly not dating each other. It occasionally causes some confusion with people a generation older than us who aren't familiar with that usage.