Search Results: forgive cheating girlfriend

So my boyfriend has been my best friend for 5 years. In high school we dated for about 2 years. Then we broke up for 2 years. Now we've been dating for almost a year again. Best friends through it all, and friends with benefits for a while.

But I just found out I'm high school he cheated on me for a few months before breaking up with me. And he then basically dated the girl for that summer when we were broken up. They were just talking, hanging out, and kissing on the cheek. This girl became my friend once we broke up and was like the main one I leaned on and who supported me through the break up, me never knowing. I suspected he was with another girl but he would never tell me who. After all this time I just found out this month, and we talked through it and everything. I can forgive them, but I don't know if I can get over it and forget it. It sucks bc this relationship we've had now has been amazing, much better than when we were young and dumb, we've been really happy and healthy. I don't want to give that up for something that happened a long time ago, but I can't trust him now (i already have trust issues from childhood trauma!) And i don't want to be that toxic girlfriend who always goes through his phone, i hate that. But that's how I found out, because I suspected it still and it still hurt not knowing and he let me go through his phone so I found out. But since he lied to me for so long it just makes me sick to think it barely affects him now and he never would've told me. Also back then, they broke it off bc he never stopped loving me and realized he never liked her like that he'd just think of me, and he broke his heart talking to other guys. So I don't know. What would you do in my situation?