New York Consolidated Laws, Domestic Relations Law - DOM § 248. Modification of judgment or order in action for divorce or annulment

Where an action for divorce or for annulment or for a declaration of the nullity of a void marriage is brought by a spouse, and a final judgment of divorce or a final judgment annulling the marriage or declaring its nullity has been rendered, the court, by order upon the application of the payor on notice, and on proof of the marriage of the payee after such final judgment, must modify such final judgment and any orders made with respect thereto by annulling the provisions of such final judgment or orders, or of both, directing payments of money for the support of the payee.  The court in its discretion upon application of the payor on notice, upon proof that the payee is habitually living with another person and holding himself or herself out as the spouse of such other person, although not married to such other person, may modify such final judgment and any orders made with respect thereto by annulling the provisions of such final judgment or orders or of both, directing payment of money for the support of such payee.