He is EITHER waiting for you to kick him out,
OR he is hoping to crush your mental health sufficiently that you willSbe the one who will choose to leave (without the kids).
SO THAT - he will be financially better off, and even move the other woman in to your house.
This happened to me. Over a lengthy period of time ex would say he wanted a divorce, but not do anything about it, not see a solicitor and take no action. One day he admitted his behaviour was intended to 'bully me out of the house' and that 'he wouldn't stop until I left'.
It is really, really hard to accept but no reasonable person does this.
An ABUSIVE person does this.
A reasonable person takes the time, sits and negotiates with respect, dignity and fairness.
It must be an incredible shock for you to be experiencing this. But I'm afraid it IS likely to get worse
AND it is ALL ABOUT THE MONEY.
I'm sorry to have to say it, but you do not have a happy marriage and he has probably been planning it for a year or two.
It is an awful, awful position to be in, but you will survive. Better to know now rather than find out in another ten years time what sort of a beast he is.