boyfriends ex......(sorry it's long)

when me and my boyfriend first got together i knew that he had an ex of 5 years that cheated on him. but what i didn't know at the time is that his whole family still let her visit and loves her until month #2 with him. i was depressed the whole 2 weeks she came and visited the family while my boyfriend was there. (most nights. some nights he'd stay with me) when she left he said i'd never have to worry about her again. so i never did. but i always stalked her because she is like society's idea of perfect. the big boobs, big butt, slim type of girl while i don't have boobs, barely an ass, i'm just a stick. then recently like a month ago.... he spent the night at his moms house and i stalked her because his family was visiting and i wanted to see if she was too. SHE WAS. he says he didn't know but 🤷🏼‍♀️🤷🏼‍♀️🤷🏼‍♀️. anyway, i made him come home. then he kept arguing to me when he came home that he doesn't want her and that she moved on and shit and all i said is that i don't trust them together especially at night because FIVE YEARS. like who would??!!? then he went back 2 days later and stayed for 3 days while i went to a friends house and got drunk and cried. after those 3 days he stayed home for the rest of the time she was there.. BUT his family would still message him talking about her and it got to the point where i hated his family and i hate feeling like that but they made me feel very insecure and i just need advice on what to do because i know its always gonna be like this and i dont wanna leave him but its draining me.