Man whore

Basically I'm in my second ever relationship my first was my school boyfriend we were together from 13-17 I lost my verginty to him, now in my second relationship been with this guy for a year and 2 months now at first he didn't confirm we was in a relationship but I though we was so he slept with someone else which I don't really mind to much about because he says he didn't think it was searious because he's 22 and I'm 18 after we officially got together he slept with another girl behind my back I forgave him it's been 10 months since he has changed don't get me wrong he don't go out anymore so I know there's no cheating but I can't seem to get over these girls I know I am prettier than them not even being vein but I will always go out of my way to look at their pictures and stuff, they never leave my mind I don't know how to forget about it& it's just stress on the relationship because I think about it so I will mention it😞
Also he has had loads of people he has slept with and there all from the same area where I've only slept with one other person I just feel like I'm not experienced enough for him I don't know why but yeah😕 help?