If you can show cause as to why you signed something you didnt agree to I would think you have a case - Can you prove he is abusive?
There is always something you can do, whether it results in what youre looking for is another story. But you CAN fight it, you just have to find an attorney willing to take on that fight...

I'm basically going through the same thing, except it hasn't gone to court yet. The settlement states I get only about 1/3 the value of the house, even though I'm entitled to half. Reason I'm going along with it is because if I don't, he threatens to problong the divorce and tells me I "can't fight his family's money", which is 100% true. I don't have the money to keep paying my lawyer, but his family has mega funds for whatever he wants.