Clearly it is time to focus on yourself and your kids, of course this is very hurtful but try to change your perspective about it realize that him breaking things off with you is actually better because it’s better to be alone then with someone who has no respect for you whatsoever because if he would have respected you he wouldn’t have cheated in the first place. Think of it as an opportunity to heal and make yourself greater. Your life does not revolve around him, you existed before him and you will continue to exist after. The best thing you can do in a hard time is to not make yourself a victim but a fighter, better yourself for you and your kids. He is a complete waste of your time and you deserve much better, the fact that he feels no remorse shows that he does not care about you so why waste any more of your energy caring about him? Care about you and your kids. Actions speak louder than words, he is the one who decided to do that and it has nothing to do with you, you are separate people and he chose what he wanted to do in that situation. Also the fact that he thinks he can justify his way out of cheating is disgusting and unacceptable, there’s healthier ways to deal with “ feeling miserable”. Feel the emotion of sadness/anger or whatever you are feeling, acknowledge it and let it pass do not let it consume your whole life and do not dwell upon it because there is no point, why be sad when you can be happy? I really do wish the best for you and hope you rise up out of the situation and turn it around, don’t waste time dwelling on someone who does not care about you. Go do what you have to do to make yourself happy. Find yourself and find God.