DeMatteo v. DeMatteo

Massachusetts SJC established the "two-look" test: a prenup must be fair when signed AND not unconscionable when enforced. Among the most demanding substantive-fairness frameworks in the United States.

Why this case matters

DeMatteo is the leading Massachusetts authority on prenup enforceability and remains controlling. The two-look standard is what makes Massachusetts a relatively unfriendly state for one-sided agreements — courts retain real power to refuse enforcement after the fact. For high-net-worth couples in Massachusetts, designing a prenup that will survive the second look at year 20 is a much harder problem than designing one that's fair at year 0.

The facts

The DeMatteos signed a prenup before marriage. The wife challenged it at divorce. The Massachusetts Supreme Judicial Court used the case to clarify the standard for evaluating prenups under Massachusetts law, which had not adopted the UPAA.

The holding

A prenup is enforceable only if it is "fair and reasonable" at the time of execution AND is not unconscionable at the time of enforcement. The court explicitly framed this as a two-step inquiry: (1) substantive fairness at signing (was the deal acceptable when made?); and (2) substantive fairness at enforcement (do current circumstances make holding the spouse to the deal unconscionable?).

What it means for you

• Massachusetts prenups must satisfy fairness review TWICE — at signing and at enforcement.
• Substantial changes in wealth, health, or family situation over the course of the marriage can render an originally-fair prenup unenforceable.
• Long Massachusetts marriages create the most enforcement risk for prenups: more time means more opportunity for circumstances to change unconscionably.
• Sunset clauses (the prenup expires after N years) are one way to manage the two-look risk — but they're a substantive concession.

Primary source

The full opinion is available at: https://caselaw.findlaw.com/ma-supreme-judicial-court/1142311.html

Massachusetts prenup law in context

Massachusetts prenups are governed by Mass. Gen. Laws ch. 209, §§25–26 — official statute text. For the full cost breakdown, attorney rate ranges, and procedural requirements, see the Massachusetts prenup cost guide.

To check whether your specific situation has the kind of risks DeMatteo v. DeMatteo identifies, take the 60-second prenup quiz — it applies Massachusetts-specific rules to your answers.

A note on legal citation

This page summarizes a published court opinion for educational purposes. We aim for accuracy but recommend reading the primary source linked above for the controlling text. Court opinions can be modified, distinguished, or overruled by later decisions; for current law, consult a family law attorney licensed in Massachusetts.