N.Y. Dom. Rel. Law § 211
A matrimonial action shall be commenced by the filing of a summons with the notice designated in section two hundred thirty-two of this chapter, or a summons and verified complaint as provided in section three hundred four of the civil practice law and rules. A final judgment shall be entered by default for want of appearance or pleading, or by consent, only upon competent oral proof or upon written proof that may be considered on a motion for summary judgment. Where a complaint or counterclaim in an action for divorce or separation charges adultery, the answer or reply thereto may be made without verifying it, except that an answer containing a counterclaim must be verified as to that counterclaim. All other pleadings in a matrimonial action shall be verified.
N.Y. Dom. Rel. Law § 211