Toxic Relationship

Hey ladies! I really need some advice. I’ve been with my boyfriend for 3 years now and we have 2 girls together. He’s cheated on me multiple times in the past and I’ve found him sneaking around on dating sites and stuff as well. I know you’ll all say to just leave him but it’s harder when you’re actually in the situation. He has since been good to me from what I know but I can’t help but feel this constant anxiety of not knowing what’s going on. My mind is constantly wandering and it is so exhausting. I can’t live like this. I don’t want to break up our family especially if he is being good to me now but I just can’t seem to shake this. It’s been 2 years since he actually physically cheated on me and still to this day it crosses my mind. I don’t know how to get past this or what to do. And yes I’ve talked to him about it and he says he’s being good to me and eventually I’m going to have to let it go. But all I ever do is wonder what he’s doing. It consumes me. My life literally revolves on basically keeping tabs on him.