Wow. This is a lot to take in. Sorry you're going through it...but I think you've handled him as well as you can.
He's a kid throwing a tantrum, so walk away. The more reaction he gets from you, the worse it'll get.
He's attacking out of fear--maybe fear that he will collapse financially. His spiritual health/love is at the bottom of his list now.
Don't be afraid. But seek legal counsel. Talk to the children about their needs to see their dad--always in a positive way.
Don't badmouth him to your in-laws. Assume everything will go to him.
Can you have NC for at least a week? I hope so. You might write him a note to say you need a week to think things through and that you will get back to him. Then, NC.
Don't know what else to suggest. Prayers for comfort going your way.
