If you signed a separation agreement that contains the required language that agreement is a contract between the two of you that is binding. Show it to a local lawyer ASAP (something you should have done BEFORE signing.)
Under the rules governing the conduct of attorneys in New York it may be necessary to remind you that this answer could be considered attorney advertising.
Under the NY Domestic Relations Law, your agreement can be enforced if it contains the requisite language to qualify as a marital agreement and if it is properly acknowledged. A simple notarization is insufficient. You should consult with an attorney as soon as possible to have that agreement reviewed. Your attorney will advise you if it is a valid agreement under NY law. If it is not valid, you will have the option of going to family court to address just custody and support issues or to go to Supreme Court to address divorce, property, custody and support issues.
You should contact an attorney and have the agreement reviewed to ensure it meet New York State requirements. Also, under NY law reconciliation voids an agreement unless there is a provision which specifically requires reconciliation to be in written form. Remember a separation agreement is a contract, it is not an order. If you are fearful of your husband taking your child and leaving your should file an emergency application in Family Court.
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