My first cousin is 18 and graduating high school next month. He hasn't any SO's for more than a few months here and there (he admits to being a player) and will be newly in college by my wedding in Oct. Since Christmas, he's dated 5 different girls. He always has another lined up when the current one fails.
Do I treat the flavor of the month as being his SO and invite her? Invite him with plus one? Or am I obligated to invite him with anyone?