I'm ruining my relationship....

I am constantly accusing my boyfriend of cheating although I don't think he ever would. I'm with him 24/7 and if for some reason I'm not, (being at school), we text each other until we see each other. I go through his phone multiple times a day, and I never find anything. He deleted all his social media back in October but a few days ago got his Facebook back to be able to talk to old friends (guys) and such and I have his password and stuff and I find myself on his Facebook more than my own now 😞 I've tried to leave him a lot over this and it's ridiculous. I don't know what to do. I tried to leave once and he started crying in front of his family and told me he isn't ever going to cheat on me and could never put me through that, and his brother told me he has never seen him cry over ANYONE. Can someone help me stop this obsession? Before he gets to the end and finally leaves me 😞