Order unanimously modified and, as modified, affirmed, without costs, in accordance with the following memorandum: Plaintiff commenced a divorce action on the ground of cruel and inhuman treatment on June 8,1979. On May 20, 1981 he sought to supplement his complaint to allege a cause of action based upon adultery. The acts which formed the basis for the allegation of adultery occurred on or about December, 1980. Section 236 of the Domestic Relations Law is divided into two parts; part A which governs actions commenced prior to July 19,1980 and part B which governs actions commenced on or after that date. Therefore, the date on which an action is commenced is generally determinative as to whether part A or part B controls (see Valladares v Valladares, 80 AD2d 244). Although plaintiff commenced the initial action based on cruel and inhuman treatment prior to July 19, 1980, this does not enable him to bring his claim for adultery within the ambit of part A. The acts upon which plaintiff bases the claim of adultery occurred subsequent to July 19,1980 and should be governed by part B of section 236. Thus, if plaintiff prevails on the ground of cruel and inhuman treatment part A is applicable. If plaintiff prevails on the ground of adultery part B is applicable and if plaintiff prevails on both grounds part A is applicable (see Valladares v Valladares, supra, at p 257). (Appeal from order of Supreme Court, Monroe County, Provenzano, J. — divorce, supplemental complaint.) Present — Simons, J. P., Hancock, Jr., Doerr, Moule and Schnepp, JJ.