Signing a prenuptial or postnuptial agreement is only the first step. This post walks through what New York courts consider when one spouse wants to disregard the agreement.
Key Takeaways:
- New York requires prenuptial and postnuptial agreements to be in writing, signed, and acknowledged the same way a deed is recorded.
- Postnuptial agreements face closer judicial review than prenuptial agreements.
- Full financial disclosure at signing is one of the clearest factors separating an agreement that holds up from one that does not.
Most couples who sit down to sign a marital agreement are not thinking about a future divorce at all. A prenuptial agreement often gets folded into the busy weeks before a wedding, tucked between tasting menus and seating charts. A postnuptial agreement tends to arrive at a quieter, more private moment: after a business sells, after an inheritance lands, or simply after a few years of marriage make both spouses want to put something in writing that never got settled at the start. Neither spouse is usually picturing a courtroom when they sign.
That is exactly why the agreement's quality matters. If a marriage ends later, a judge who wasn't in the room when it was negotiated will read the agreement closely, relying on the document and the circumstances surrounding its signing.
A spouse who feels blindsided by the terms years later will often ask the court to set the agreement aside entirely. Understanding what actually makes an agreement durable, rather than vulnerable, gives both spouses a clearer sense of what they are signing and why.
The Basic Legal Requirements Under New York Law
New York Domestic Relations Law §236(B)(3) sets the baseline. A prenuptial or postnuptial agreement must be in writing, subscribed by both parties, and acknowledged before a notary in the same formal manner required to record a deed. An agreement that skips this formality, even one both spouses genuinely intended to honor, risks being unenforceable, no matter how fair its terms are.
This requirement exists because oral understandings and casual written notes do not carry the same weight when a marriage ends and memories of what was agreed no longer match.
Why Postnuptial Agreements Face a Higher Bar
A prenuptial agreement is negotiated between two people who are not yet married, generally treated by courts as an arm's-length contract between two parties looking out for their own interests.
A postnuptial agreement is different. Once a couple is married, each spouse owes the other a fiduciary duty, and that changes how courts evaluate any financial agreement they sign afterward. In Petracca v. Petracca, the Appellate Division upheld a decision to set aside a postnuptial agreement after finding the wife had waived a significant interest in her husband's businesses without adequate disclosure or fair terms at signing.
The case remains a frequently cited example of how closely New York courts examine postnuptial agreements once a marriage is already underway. A prenuptial agreement drafted with the same rigor that postnuptial agreements require tends to hold up better in either scenario.
Full Financial Disclosure Is Not Optional
Before signing, both spouses must disclose their assets, debts, income, and expected inheritances. Years later, a court will ask whether each spouse knew what the other owned and owed at signing, as this postnuptial agreement overview explains. If one spouse later finds an undisclosed business, investment account, or property, the agreement becomes much easier to challenge, even if everything else was done correctly.
Attorneys who work regularly with forensic accountants and business valuation professionals are better positioned to make sure this disclosure is thorough rather than superficial.
Independent Counsel Protects Both Spouses
An agreement negotiated when only one spouse had a lawyer, while the other signed based on a brief explanation at the kitchen table, invites a later argument that the unrepresented spouse did not understand what they were giving up.
Separate counsel for each spouse is one of the clearest signals to a court that both sides entered the agreement with a genuine understanding of its terms. This protects the spouse without counsel from an unfair result, and it protects the agreement itself from being unwound years later.
Courts Judge Fairness at the Moment of Signing
Courts generally look at whether an agreement was fair and reasonable when the couple signed it, not whether it still feels fair once circumstances have changed. A prenuptial agreement that seemed evenhanded before a business grew into something worth millions is not automatically unenforceable simply because one spouse's fortunes changed. A court may still decline to enforce a specific provision found to be unconscionable, particularly if the disclosure or counsel requirements above were not met at the time of signing.
Timing Matters More Than Most Couples Expect
A prenuptial agreement signed the night before the wedding, with one spouse handed the document for the first time at the rehearsal dinner, is far easier to challenge than one negotiated months in advance with time for both spouses to review and revise it.
Postnuptial agreements carry a similar concern: one signed during a period of open conflict in the marriage draws more scrutiny than one negotiated calmly. Building in enough time for real negotiation is one of the simplest ways to protect its enforceability later.
For couples across Nassau and Suffolk Counties weighing a prenuptial or postnuptial agreement, the details covered here are the same details a Nassau County Supreme Court judge in Mineola would examine if the agreement were ever challenged. Joseph Law Group, P.C. has drafted these agreements for Long Island families since 1998, and our team includes attorney Jacqueline M. Caputo, who focuses specifically on postnuptial agreements and prenuptial matters alongside the firm's broader work in property division and high-net-worth divorce.
Book your free case evaluation to talk through what a durable agreement looks like for your situation.
