Confused About What Boyfriend Says

Kimberly
I've been with my boyfriend for around 2 1/2 years. From the beginning of the relationship and still to this day he brings up/mentions/talks about his ex girlfriends and ex fiance. I have tried to explain to him how it bothers me and that I would rather he not talk about them still - I understood why he brought them up at the beginning of our relationship because they cheated on him, financially used him - in another words used him. So, he had some issues and fears that he'd end up finding another girl like them. Then he occasionally mentions that he misses their big boobs, their bleach blonde/platinum blonde hair, and certain things they did sexually together - which I know I have microscopic boobs and I'm not as sexually smart as those other girls because I've only ever had sex with my ex. Yet when I brought up my ex boyfriend at the beginning of the relationship with my new boyfriend, he got upset and said something about how he rather not hear about my ex, so respectfully I don't mention him. I'm not unhappy with my current boyfriend - I love him and am happy to be with him he's been here for me through a lot of tough times. I just don't know how to handle the continued comparisons to his ex's (because I know who most of the girls are that he is talking about and they have nice curvy looking bodies, big boobs, blonde hair girly girls - then theres me with some curves, slightly over weight, dark hair, trouble with achne and a tomboy) and I'm not sure how to approach trying to talk to him about stop talking about/comparing me to his ex's again.