i love an ugly fat bad girl why ??

hi hope you will answer my question it s driving me crazy. well i have been with this girl as friends for just 1 month then we started being in a relationship but with a lot of ups and downs breaking up and return always it has been like this for three years !! she always make mistakes i do but less then her. i felt real love for her now i'm confused if i still love her.now she wants to not talk to each other because of our fights.i feel that we're done now we can not return to each other she isn't of my type at all she treates me bad everything but the problem is that when she's not around i miss her and want her don't know why!! she just apologizes and we return every time i'm sick of my self why is this hapening to me i'm around beautiful girls but i think of her why?? what should i do now ?? help i appreciate every answer thaanks a lot