Playing the dating game isn't easy when you're trying to rebuild a galactic alliance - so imagine Leia's dismay when every she seems to find a nice guy, they quickly find an excuse. Apparently having abrother who destroyed the Death Star, is the last of the Jedi and carries a lightsaber around is a major turnoff for most guys - no matter how much of a dork the afformentioned Death Star destroying Jedi brother actually is.
Post-RotJ, Luke's reputation scares off Leia's boyfriends