Cheating...😔

My boyfriend of a year and 4 months cheated on me with another girl (making out with another girl at a party drunk) and then after that he promised not to do it then tried hooking up with a girl I was suspicious about... It happened 6 months ago.. But I still am not quite over it and he gets mad if I bring it up... I'm super self conscious and he's had 6 other partners before me... And I've had 5.. But he never is self conscious or anything and I am. I'm always comparing myself to them... Help