Unlike other matrimonial agreements made in contemplation of marriage or during the marriage, property settlement agreements (PSA) are termination agreements made at the end of a marriage in contemplation of divorce. A PSA is a judgment in a divorce case that determines the distribution of the marital property between the divorcing parties. In other words, it is a contract that divides up the assets of divorcing spouses and incorporates it into a divorce decree. PSAs are, for the most part, final and irrevocable. Like most contractual agreements, PSAs are enforceable absent evidence of fraud, mutual mistake, fairness, legality, or other valid contractual defense. However, the law recognizes that circumstances which existed at the time a property settlement is entered are subject to change. Hence, subsequent to a property settlement agreement, a party may seek a modification of its terms if they can provide evidence of changed circumstances. The moving party must prove that, left unchanged, the property settlement agreement would result in extreme and unexpected hardship.