Hi, and welcome! Sounds like you are doing some good work on providing for your family. And good for you on the therapy.
Please make an appointment with a lawyer. It could be that your divorce would be relatively simple. He clearly isn't capable of caring for the children, so he's hardly in a position to fight you for custody. Do you own property together? Where are you living?
Several people here have handled their own divorce by using a lawyer just to look over the paperwork and make sure it's done correctly. You want to be sure that everything is done right because of the children. But really, you might be surprised how little it would cost you financially, and it might bring a huge sense of freedom to cut yourself loose.