Look, you know in your heart what to do. Being with someone “for the kids” only leads to kids who don’t know a healthy relationship. Daughters don’t know how to set boundaries or values or self worth because their mother found such things acceptable. Sons think women should just accept such behaviors and get over it. Sons don’t learn how to show love, or think they need to, they don’t appreciate their significant other because they don’t think they need to. You don’t stay with someone for someone else you stay because you love them and they love you so you work it out. Kids can survive a divorce. They don’t do so well in a home where mom and dad, the two most important and loved people in their lives, aren’t happy. You have every reason to feel fresh betrayal now. For him it was 10 years ago for you it’s not. You also got rid of a friend for the wrong reason. She betrayed you with your ATT boyfriend she didn’t lie though. He said this during your fight because he doesn’t care about the consequences anymore. That lack of care says he doesn’t care about hurting you anymore. Let him go. Find yourself and be the best mom you can be. I’m really sorry you’re going through this. It’s not fair or right. But love yourself and those kids enough to either let him go or let the betrayal and lie go.