Cheated on and feeling lost

My boyfriend and I have been dating “exclusively” for 4 months. But Saturday I had a nagging feeling I needed to check his phone, specifically messages with his ex girlfriend.

Back story, he was upfront when we started dating that he had an ex he was friends with benefits with but that if we decided to make it exclusive he would end the “benefits” part of it. I let that go and we continued dating. At one point he sent me a dirty picture and then tells me he sent her the same one. I felt sick at the idea and it started an argument where I almost called it quits but he asked me to instead give “us” a chance because he really liked me and promised to tell her.

Fast forward 4 months, things were seemingly going great. We had said I love you, met each others kids, the kids met each other, everyone seemed happy, my kids adore him, and I was naively picturing a full on future with this man.

Then comes Saturday. He was napping and I couldn’t shake the feeling that I needed to see his messages with her. So I opened his phone and looked. What I found was dirty pics, ***, making plans to hook up behind my back, him telling her how things with me were great but he wanted his life with her back and that I was a sweetheart but a “rookie” in the bedroom (ouch) versus how good she used to be, etc. At one point she even seems to feel guilty bc she tells him as much as she wishes it was her, his path is with me now, and he asks if she would really say no given the chance?

I took pictures of the some of the worst of it on my phone while I was waiting for him to wake up and I didn’t even get through all of it. When he woke up I started bawling, and confronted him. He admitted to everything, that it had never ended after he asked me to be exclusive, but tried to justify that it never became physical. I argued that it would have if she had ever made it up for a visit like she was supposed to but cancelled. (She lives 2 hours south of him now). He agreed I was probably right that he would have slept with her and never told me. But throughout the whole thing he’s begging me to give him a chance because he wants a life with me.

To make things even more twisted, let’s throw my background in. I’m working through a divorce my ex keeps dragging out, and I was blindsided in different but still awful way by him too. And as a result of that he hasn’t been allowed to see our children (age 13 and 10) in 2 years. Boyfriend knows all of this. He also knows he’s been the first man I’ve allowed to meet my children since their dad left the picture.

So between his puppy dog eyes and the idea of ripping another man out of my kids life so abruptly, I just… couldn’t. I told him I’d give him one chance and one chance only but that I needed proof of him ending it. Which he did provide. But then yesterday I was crying all day on and off, being snippy and admittedly a little mean to him, and he started questioning our relationship, which made me mad, bc after what he did shouldn’t that be my call? And today he turns the tables on me and starts complaining about how I “violated his privacy” when I went onto his phone. I tried explaining the nagging feeling and asked if he would have opened the messages for me if I had asked him to. The best he could do was 🤷‍♂️

I already questioned whether or not I would want to get remarried down the line but this felt like it solidified to me that I will NEVER marry him. Not tomorrow, not 20 years from now. My divorce has been a nightmare and should it come to it, I want to be able to walk away without all the extra drama.

I can’t do another toxic relationship, things with my ex husband had gotten so bad I was throwing up from stress multiple times a day. When I ended my marriage, it magically stopped.

He's supposed to be coming over to my house tomorrow for dinner. This was planned before he was busted. But now I’m questioning everything while my kids clean the house (😳) for the visit and chatter on excitedly about him coming over.

I need help. Either advice on how to get through this or how to find the strength to tell him to *** off and have fun with the ex. And what do I say to the kids? I never wanted to be the mom with a revolving door of men in their life.