How do I stop this ??

So me and my Boyfriend where best best friends before we started dating we always there for each and tell each other everything and this may sound weird but we were like brother and sister, well since we were so close he told me bout his gf at the time and I was there for him when they got together and EVERY time she broke his heart ! But I also knew how much he loved her he talked about her with so much love and well ....... I'm basically the opposite of her , she's everything in not , she a mechanic ( my bf a diesel mechanic) she's beautiful,she has a tan and beautiful brown eyes and brown hair big boobs and ass and their both so much alike personally wise.....: while I am VERY pale ,red hair ,gray eyes,small boobs and ass his ex is dead set on taking him back for herself even tho they got together and broke up 10 times , how do I stop wishing I was more like her ?????? When they were together he said she was perfect..... how can I just be confident as myself???