Sabotaging your first day back at work is going to be a juicy, low hanging fruit, unfortunately. A PP who mentioned the extinction burst is right.
Please, please get your back up plan in place now. He has been stupid enough to verbally abuse you on paper, he's one of those types who wouldn't care about a bollocking from a judge in the family court, he just wants to shit over your life, because he is losing control.
I know you have been apprehensive about getting your parents on board, but do they know the full picture that he's being abusive to you, that he doesn't even have basic medication for sick children? I know parental relationships are different for everyone, but mine would stop at nothing to support me if I was with a guy like Twattoo.