If he is used to you being the one who gives in, the one who smooths things over even at your own expense, then "180". If you usually tell him everything, don't give him any information to work with that is not strictly necessary - such as stuff to do with the children or whatever.
So, for instance, if you haven't told him already, do not tell him you are going out tonight. Just tell him when you will be back (for the children's sake). Shift that balance of power NOW.
If you normally get guilted into doing various tasks, stop doing them (again, unless the children are involved). Do not do anything for him, nothing. If there is dirty laundry of his, he can take it to Daddy's to wash. If there is important mail of his coming to the house, ignore it.
He's on his own now, he made that choice.
What a situation. OW ay Mummy's, your H at his Daddy's, OP, YOU are the mature one here. You are the strong adult whose life will go from strength to strength.