As a general rule, an agreement is enforceable as per its plain terms. If the agreement says it is "unmodifiable," then most courts would conclude it is just that. That said, an agrement is enforced by its terms (i.e. by its *exact* language) and different judges see things different ways; if this is economically killing you (which seems to be the case), bring the agreement to a reputable local divorce/family law attorney (you want a local lawyer, since they will know how the local judges tend to view things) to review with you, to see what options you might have.