I'm sorry you're getting so much stick for this OP! Whilst I can understand where all the abuse is coming from, I understand what you're saying too.
It can take years to get over someone, and what are you supposed to do in that time? Just sit around and feel sorry for yourself? What if you do come across someone you like? Should you be like 'oh sorry I'm still not over her from 2 years ago' or would you give it a shot which could possibly give you the push you need in order to get over your previous partner?
I think that as far as first loves go, or whatever, sometimes you might not completely get over them, and are constantly thinking 'What if?!' but at the end of the day, you're getting nowhere with it. The same thing happened to me, and I've just learnt to accept that it wasn't meant to be. I am much happier accepting that I am not meant to be with that person, and that one day I'll meet someone better (hopefully!). You've done good cutting her out of your life, and that's the way it needs to stay.
As for your current girlfriend, are you sure you want to be with her? I'm not sure that "how to get over her not being pretty" is the main issue here. Unfortunately, I don't think being with her has had the desired effect I previously mentioned, about her possibly helping you get over someone, so I'm not sure what the point is in you staying together. Physical attraction is important, and if you are still thinking 'what if?' over somebody else, then it isn't fair on her. But I understand you aren't trying to be malicious.