N.Y. Dom. Rel. Law § 248

§ 248. Modification of judgment or order in action for divorce or\nannulment. Where an action for divorce or for annulment or for a\ndeclaration of the nullity of a void marriage is brought by a spouse,\nand a final judgment of divorce or a final judgment annulling the\nmarriage or declaring its nullity has been rendered, the court, by order\nupon the application of the payor on notice, and on proof of the\nmarriage of the payee after such final judgment, must modify such final\njudgment and any orders made with respect thereto by annulling the\nprovisions of such final judgment or orders, or of both, directing\npayments of money for the support of the payee. The court in its\ndiscretion upon application of the payor on notice, upon proof that the\npayee is habitually living with another person and holding himself or\nherself out as the spouse of such other person, although not married to\nsuch other person, may modify such final judgment and any orders made\nwith respect thereto by annulling the provisions of such final judgment\nor orders or of both, directing payment of money for the support of such\npayee.\n