Trust issues

So, my BF is super handsome and I have some self esteem problems, I don't feel pretty enough or skinny enough to be with him, he use to get tons of likes on his selfies in social networks and he used to like all these girls with amazing bodies! I always feel he is going to cheat even though he swears he's never going to do it!!! How can I build up my trust? Can I really trust him?