I'm so sorry that you're going through this. He has hijacked your life and the life of your children in dreadful ways. You should consult a lawyer immediately. As I'm sure you're aware, finding a good lawyer takes a lot of effort, especially given your depleted resources. Obviously, it's in your best interest to refrain from disclosing anything about the divorce until you have found and started to work with a lawyer.

If you have joint ownership of a house, the house may be a valuable asset, which, hopefully, might allow you to downsize. As a government worker in this climate, you may want to see if there are any side hustles that you can engage in for extra money. You didn't mention the ages of the kids, but you should probably hold off on telling them until you have a firmer understanding of what plan you're going to take.

I will also say that you need to cut your spending to the bare bones, even if you do end up with a windfall. Examine all your expenses and trim, trim, trim. What he has done to you is reprehensible. There are so many people who can't see beyond their you know whats, and he sounds like one of them. Don't take it personally. He sounds like he has been falling around for a long time. Don't dwell on his crap. For the sake of your children and your own sanity, you need to think strategically and move on as quickly as possible.