I can't help feeling like a failure. You know you want your kids to grow up in a two parent home in a loving environment
OK....Reality check!!!
YOU are not the one who left the home. YOU are the one still with the kids, desiring a two parent home. Your H. is the person that broke up a two parent home. Your H. is the one that had an affair resulting in an OC. You were the one willing to accept the OC into the family. After going through all that, he turns around and walks out on his OC, too!
Secondly, this home cannot be a two parent "loving environment" if your H. keeps up with his current behaviors. His behaviors are not loving...to you....or your children. Not only are his behaviors not loving, look at what he's role modelling for your children!
If your H. was really interested in rebuilding your marriage, he would have gone to counseling. If your H. was really interested in rebuilding your marriage, he would have understood how upsetting this new information is for you. Even IF the OC is not his, he still should understand how very difficult it is for you to hear this information. But, no....he walks out the door and says you kicked him out. Mr. Martyr, Victim. Trying to distract attention from HIS misbehaviors.
Your H. might be interested in "maintaining" your marriage...as is....but not in rebuilding or recovering a healthy marriage. He has done nothing to work toward that end.
Your H. thinks that he wouldn't be so stupid as to repeat the same mistake twice? What has he done any differently to make sure he didn't fall into the same types of behaviors? I suspect that his original affair and birth of an OC wasn't a logical, rational, well thought out decision! So, what does intelligence or stupidity have to do with it? Obviously there's some other psychological issues going on here. And, he's not willing to do the work to heal himself and the marriage. And, YOU can't do it on your own. (If I were a betting person, I think that the odds are that this OC is or very well could be his.)
Numerous people have suggested getting legal consultation and counseling. Where are you at with those ideas? It seems that you're focusing too much on his crappy behavior and choices, while denying your own needs. I would suspect this might go on often in your relationship. The focus in on him....what he wants and needs...and not on you. You cannot change him right now.
It sounds like you did everything you could to work through the first affair incident, and now this. Your cooperation and support the first time around did nothing to change his behaviors.
I think that if you keep focusing on getting him to change, whether through love, cooperation, or a 2x4, this "dance" is going to keep going. Do a little self care. Show him that at least you are going to start having some respect for yourself, even if he doesn't. You can still love him, still want him back, still be sad, lonely, angry, etc. You don't have to make any final decisions right now. But, you need to be there for your children, to role model self-respect and self-care.
It sucks that you're the one with all the responsibility. It's not fair. But it is how it is. Spending your energy chasing after him, trying to change him, is going to wear you out. It'll be a waste of time and energy because you can't change him.
Work on changing yourself. "Change" in terms of self-care, financial care, legal support, counseling, etc. Again, you don't have to make any final decisions right now. But at least know what your options are. The "option" of changing him doesn't seem to be working. And it's ripping your heart out.
If what your H. wants is some young, dependent, skanky bimbo, you can't be one! I couldn't be one for my xWS. I'm 50, not 21. I'm independent, responsible and have some "class" (according to my step-daughter!) Your H. obviously doesn't want one for very long, because he moved on....to the "same person" with a different name and face.
I know that you're confused and hurting. Please, please, please get some support and help! We care, but you need someone who can get the whole picture and help you heal.
Please let us know how you're doing....and if you've gotten some help. You deserve it.