It all depends on the circumstances surrounding the divorce matter. You could rebute this as coercion or duress, though. I also don't know what he is asking for and what legal grounds he has. Most Pro Per's don'tunderstand community property and separate property laws and how all of this is divided so I suspect he has gotten it wrong. But, your susceptibilty make me question your skills at handling this on your own. You need to seek legal counsel to get feedback on this matter and representation. At least seek an attorney who can give you a free consultation on this.
If you contest the agreement, the court will hear evidence as to the circumstances under which the agreement is signed. The court also has the ability to determine whether the agreement is equitable.
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