I read this entire thread yesterday with a lump to my throat, and did not post.
I see that WWIFN have pointed out the concerns I had, so very eloquently, and with much insight.
I am not going to be so kind to him in my summary:
He allowed himself to enter into an adulterous relationship. He introduced his and her children to eachother and ensured they were enrolled in the same ballet classes. He met his new woman with your and her children, and were admittedly hugging in the playground, in open view, but not in front of the children. He brought his new woman to your home and your bed. He was prepared to break up your marriage and leave you for her, he even thought he could handle only seeing his children twice a week so he could move on with her.
What happened?
The affair was found out, and the OW decided to stay with her husband. Next, being separated from you he realized he could not realistically only see his children as a part time dad. (What about you?) I gather he also had some pressure put on him by his moral and Catholic family. Divorce is not really possible, unless granted by the pope for some very good reasons, isnt that so? And adultery? tut tut.
I dont see any particular mention of you, or concern for you, let alone any concern for his own children in this. Aside from preparing them for his new woman early on and familiarizing them with her kids.
I am sorry for you and your kids. I really hope you find a way to move on from this, with or without this pathetic, calculating scumbag of a man. Sorry.
And if you DO decide he is worthy of a second chance, you call the shots. And reread wwifn's post below and ensure he moves to a different job and cut out of his life all the people he collaborated his affair with: people he rubbished you and your marriage to.