You need to really focus on you and the kids. If she wants to come for the ride, fine. You don't need to obsess about the other man. Face it, there probably is one and it's probably been going on for a long time. Now that that's out of the way what are your plans? You and the kids have something going soon? Make your life what you want it to be, that's very attractive to women. After all, you're not dependant on her for your happiness. She's a liar, an adulterer and a marginal mother. Just focus on you and your kids.