Your ex husband cannot just stop paying child support if a court has ordered him to do so. Whether you should sign something he has requested cannot be known from the information you have disclosed. It would be very helpful to at least consult with an experienced family law practitioner to review his support obligation.
Best wishes for an outcome you can accept, and please remember to designate a best answer.
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Please don't sign and don't let him bully you. You can at least consult with an experienced family lawyer for a few hundred dollars and find out what your rights are and where you stand. He needs to support his children.
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