SooSmith, stand back if you can and look at your situation as an outsider.
A marriage where the wife is having an affair.
November - they split, husband moves into spare room.
December - husband starts a new relationship.
Jan-Feb - couple continue to live under one roof, sharing parenting as before.
March - husband moves out of family home, straight into family home of another woman. Wife's affair ends, she approaches husband to come back. Shared parenting starts to break down.
April-May - husband abdicates all but financial responsibility towards children, dumping childcare onto the woman he moved in with around 8 weeks ago.
Can you look at it as if you're not involved? Can you see the problem?
You are in a relationship with a man who 'moves on' at speed. If you were to be a bitch and throw a strop about his wages and time being 'wasted' on his children - he would agree with you and withdraw that too. HE IS DETACHING from his 'old' life. He is moving on. And I think you know that, and it frightens you, because you know he'll move on from you as well.
I'm sorry to be so harsh, but your relationship is a sham. He is the type that needs to have a woman to stroke his ego and do the wifework so he doesn't have to sully himself with such petty details - such as the care of his children. To him, you are a convenience. You are providing a ready-made home with all mod cons and sex, for very little effort on his part
.
For your own sanity and the good of your children, I think you need to tell him he has to move out. He should find himself a home of his own where he can build some independence and a proper relationship with his children. Although I suspect he won't, not without a woman to attend to it all for him.
His ex is not your problem, she is his problem. But he is perfectly happy to shunt his problems onto your shoulders, so he doesn't have to do a damned thing.
Do yourself a favour and get rid. He'll be fine - he'll move on from you at the same sort of speed as he's moved on from his wife and children.