I haven't read any replies, but I have to point out that whatever reason you have for ending a relationship is legitimate. Okay, I can think of some exceptions, but Angel's insecurities and desires are legitimate. He couldn't be part of a relationship in which he took more than he gave. He saw Buffy as a girl with options, unlike him, who was settling for someone much older and who came with serious restrictions. Buffy and Angel couldn't really share a life, not completely, and Angel thought she deserved better. Moreover, he didn't want to be in a relationship knowing that. I find his reasoning perfectly legitimate.