If I remember right, your kids are teens. I think they are old enough to decide how much of a relationship they want with their dad now. My girls are older, both in their 20s, but neither will talk to their dad now. It's something that will take time. A friend of mine gave me a good analogy. If you have a deep wound like a cut or a twisted ankle, you are told to stay off if it and let it heal. If you put pressure on it too soon, it won't heal correctly. She told me the hurt of my girls was like this. They need time to heal from the fact that their dad has become an adulterous liar. That he left their mom for someone else. Your kids need to heal from their dad walking out on all of you. Don't pressure them. Let them heal. Then let them decide when and how much of a relationship they want.