Beautiful Girls Dating Ugly Guys?

Alright well I have this friend who's absolutely beautiful. She gets compliments about her body, hair, face, clothes, shoes, etc almost everyday and the best part about her is that she honestly doesn't even realize how stunning she is. I can't help but think this is why her BF is so ugly? She settled for something completely not in her league....but then again he treats her like an angel.....your guys thoughts?