i think what we are seeing here is the precursor to the extinction burst.
In the past his abuse of the OP has always led to him getting what he wants. He demands and she caves. But now it isnt working and he isnt seeing that she has no reason to cave any more, because he left her. In the past she did it to keep a happy (ish) home for the kids but now there is nothing forcing her hand.
So he demands again, in a louder voice. Still no. And so on, which is why holding the line is so important. Giving in out of exhaustion or guilt simply shows him that if he goes on long enough, he will get what he wants. What @mummy917 is dealing with is basically a toddler who wants ice cream before dinner.
I suspect it will culminate in him totally losing it, calling her a selfish fucking bitch because she wont do anything for him. A proper full on tantrum.