Even if a couple enters into a prenuptial agreement before marriage, the process of planning a divorce may prove that the agreement is invalid. If the agreement is not written fairly, one spouse or the other may successfully challenge it and secure different terms.
In order for a prenuptial agreement to hold water legally, both parties must fairly disclose their financial behavior, including all their assets, income and debt. If one party hides assets or debt from the other, for instance, the prenup may not hold up. Likewise, a spouse may claim that they signed an unfair or misleading document if he or she did not consult with an attorney beforehand.
In general, prenups are deals in which both sides get something. If the nature of the agreement is grossly unfair or attempts to dictate behavior outside of bounds legal authority, a judge may throw it out. Similarly, the agreement may fail if one side can make a convincing case that he or she did not understand the prenup in the first place.
It is difficult to know what grounds you may have to challenge a prenuptial agreement until you consult with an experienced divorce attorney in your city, who understands the local legal system. The differences among laws in many states and counties may greatly affect the strength of your agreement, and the opinions of the judges in your area may ultimately lean consistently one direction. With professional legal guidance you can carefully examine your circumstances and the document itself to identify ways you may challenge it while keeping your rights and priorities protected.
Source: Findlaw, "Making Your Postnuptial Agreement Enforceable," accessed Nov. 23, 2017