23 Pa.C.S. § 3331

The validity of a decree of divorce or annulment issued by a court shall not be questioned, except by appeal, in any court or place in this Commonwealth after the death of either party to the proceeding. If it is shown that a party who subsequently attempts to question the validity of the decree had full knowledge of the facts and circumstances later complained of at the time of issuance of the decree or failed to take any action despite this knowledge within two years after the date of the decree, the party shall be barred from questioning the decree, and it shall be valid in all courts and places within this Commonwealth.