Or, he could just grow the **** up already and suck it up like an adult for those kids. He's sown his wild oats, time to do what's right.
Its time to shit or get off the pot, Marc. You are a weak man and need to get yourself sorted out. Jumping from woman to woman isn't going to make you stronger, its a weakness for you. You try to find your happiness in others, and that's not how it works.
If you can't be a good partner to your children's mother, then leave her alone and just be a good father to those kids.
You need to give up Girl A as well. She deserves someone who can come to her clean, and you have way too much baggage. Sounds like she deserves better, sorry.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh