I was the daughter as well in a similar situation. My parents split up when I was 3 got back together when I was 6 and split up again when I was 9. My dad didn’t cheat but was absent and self-centered and they just didn’t work out despite being very much in love with each other. As a child, the only thing worse than your parents splitting up once is them splitting up twice. I genuinely hope this works out for you OP and you sound like a great mom but, as a soon to be mother myself and adult child of divorce, you have to put your kids before your relationship. My parents failed (though I’m sure they would disagree with me on that one...) to do that for many years and I was resentful for a long time and I still don’t trust either of them totally. Take it slow. I think you are right not allowing him to move back in yet. Date him again and see where it goes and don’t be afraid to call it quits if it isn’t absolutely wonderful. You owe it to yourself and to your children.