(a) Unless and to the extent that the decree precludes modification, any final order for the periodic payment of permanent alimony or support, an order for alimony or support pendente lite or an order requiring either party to maintain life insurance for the other party or a minor child of the parties may, at any time thereafter, be continued, set aside, altered or modified by the court upon a showing of a substantial change in the circumstances of either party or upon a showing that the final order for child support substantially deviates from the child support guidelines established pursuant to § 46b-215a, unless there was a specific finding on the record at a hearing, or in a written judgment, order or memorandum of decision of the court, that the application of the guidelines would be inequitable or inappropriate. There shall be a rebuttable presumption that any deviation of less than fifteen per cent from the child support guidelines is not substantial and any deviation of fifteen per cent or more from the guidelines is substantial. Modification may be made of such support order without regard to whether the order was issued before, on or after May 9, 1991. In determining whether to modify a child support order based on a substantial deviation from such child support guidelines the court shall consider the division of real and personal property between the parties set forth in the final decree and the benefits accruing to the child as the result of such division. After the date of judgment, modification of any child support order issued before, on or after July 1, 1990, may be made upon a showing of such substantial change of circumstances, whether or not such change of circumstances was contemplated at the time of dissolution. By written agreement, stipulation or decision of the court, those items or circumstances that were contemplated and are not to be changed may be specified in the written agreement, stipulation or decision of the court. This section shall not apply to assignments under § 46b-81 or to any assignment of the estate or a portion thereof of one party to the other party under prior law. No order for periodic payment of permanent alimony or support may be subject to retroactive modification, except that the court may order modification with respect to any period during which there is a pending motion for modification of an alimony or support order from the date of service of notice of such pending motion upon the opposing party pursuant to § 52-50. If a court finds that a substantial change in circumstances of either party has occurred, the court shall determine what modification of alimony, if any, is appropriate, considering the criteria set forth in § 46b-82.

(b) In an action for divorce, dissolution of marriage, legal separation or annulment brought by a spouse, in which a final judgment has been entered providing for the payment of periodic alimony by one party to the other spouse, the Superior Court may, in its discretion and upon notice and hearing, modify such judgment and suspend, reduce or terminate the payment of periodic alimony upon a showing that the party receiving the periodic alimony is living with another person under circumstances which the court finds should result in the modification, suspension, reduction or termination of alimony because the living arrangements cause such a change of circumstances as to alter the financial needs of that party. In the event that a final judgment incorporates a provision of an agreement in which the parties agree to circumstances, other than as provided in this subsection, under which alimony will be modified, including suspension, reduction, or termination of alimony, the court shall enforce the provision of such agreement and enter orders in accordance therewith.

(c) When one of the parties, or a child of the parties, is receiving or has received aid or care from the state under its aid to families with dependent children or temporary family assistance program, HUSKY A, or foster care program as provided in Title IV-E of the Social Security Act, or when one of the parties has applied for child support enforcement services under Title IV-D of the Social Security Act as provided in § 17b-179, such motion to modify shall be filed with the Family Support Magistrate Division for determination in accordance with subsection (m) of § 46b-231.