I suspect that what he is actually trying to do is to get you to voluntarily terminate your parental rights so that his wife, who is the stepparent, can adopt your child. If that is the case, then yes, he would be able to revoke visitation rights. If the child is adopted, she would legally be the child's parent and you would not.
I would be very leery of this, and would speak to an attorney immediately before signing anything.
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