I have absolutely no experience in this area but I'm so very glad we have so many folks who DO know what you can do to get help! I just want to say that you have not failed yourself or your kids. You believed and hoped for the best, and the A is the one who has failed.
I hope you can take action as soon as possible on the suggestions you've been offered. I agree that your AH is simply trying to beat you down and that if you look for assistance and fight him, he won't get things all his own way. A lot of resources have been mentioned, and I feel sure you can find help.
Wishing you strength and clarity.