You are a grown woman and you shouldn't be relying on anyone else as a responsible adult.
Especially since you're with a man that's had multiple wives and it sounds like he chose you because you're a much younger foreigner who he thought he could control and manipulate...which is what men like that do.
Stop signing things that you don't understand. I wouldn't never sign any document unless I had some understanding of the implications of it. And he can't make you sign anything.
See a lawyer...this isn't something you should be asking for advice on an internet forum. You need professional assistance with this because there is no doubt that this guy has done this before and he's trying to intimidate you into doing something against your best interest.
You need to divorce him and start getting your life together without relying on a man who's clearly a giant, self-serving jackass.