To many people, prenuptial agreements carry a reputation as a silver bullet that defends against all divorce woes. However, while prenuptial agreements wield great strength to protect spouses from outside parties and even each other, there are many ways that a well-intentioned agreement may not hold up in court.
Just because a prenuptial agreement exists does not mean it is enforceable. It should go without saying that any prenuptial agreement worth its salt must be in writing (but you'd be surprised how often verbal agreements come up in divorce negotiations). Even if it is written out, it must be properly executed and signed by all parties. Furthermore, neither party can sign the document under duress or without proper time to consider its provisions and pursue independent legal counsel.
Still, even if all those basic standards are met, if the document contains false or incomplete information by either party, especially when it comes to financial disclosure, then the whole document may be invalid. Similarly, if the agreement itself contains provisions that contradict the law or leave one party bearing an unfair burden while the other prospers, a judge may not honor it.
If you want to create the right agreement for your relationship, be sure to do so with proper legal counsel from an experienced attorney. If you forego appropriate legal counsel, or create an agreement that is unenforceable, you may face even greater problems in the future than if you'd never made an agreement at all. With proper help, you can ensure that your agreement protects you properly and maintains its ability to stand in court.
Source: findlaw, "Top 10 Reasons a Premarital Agreement May be Invalid," accessed May 25, 2017