Most people have heard of a prenuptial agreement — a contract signed before marriage that sets out how a couple’s finances will be handled. A postnuptial agreement does the same thing, but it’s entered into after a couple is already married. For years, these after-marriage agreements existed in a gray area of Arizona law. That has now changed: Arizona has passed its first statute specifically governing postnuptial agreements, giving couples a much clearer path.
Why this matters
Until now, Arizona had no statute that spelled out when a postnuptial agreement was valid. Instead, their enforceability was worked out through decades of court decisions — and under those cases, the person trying to enforce the agreement carried the burden of proving it was valid. That made postnuptial agreements riskier and less predictable for the couples who signed them.
The new law flips that dynamic. It sets clear requirements for a valid agreement and puts the burden on the person challenging it, which makes a properly drafted postnuptial agreement far more reliable.
What the new law requires
Under the new statute, a postnuptial agreement is an agreement made during a marriage to divide or define one or both spouses’ property interests. To be valid, it must be in writing and signed by both spouses, and it takes effect when signed.
A postnuptial agreement can be challenged — and set aside — if the person contesting it proves any of the following:
- It was tainted by fraud, coercion, or undue influence;
- One spouse signed without full knowledge of the property involved and their rights;
- The agreement is not fair and equitable; or
- It doesn’t reflect a genuine, mutual intent to divide or define the spouses’ property.
In other words, a postnuptial agreement that is entered into freely, with honest and complete financial disclosure, and on fair terms, now stands on much firmer footing than it did before.
Who might want a postnuptial agreement?
Couples pursue postnuptial agreements for many reasons — for example:
- One spouse starts or acquires a business during the marriage;
- A significant inheritance or gift comes into the picture;
- The couple wants to clarify how a particular asset or debt will be treated; or
- They simply want the clarity and peace of mind that a written understanding provides.
The takeaway
A postnuptial agreement is only as strong as the care that goes into it — and now that Arizona has a statute setting the rules, getting the details right matters more than ever. Full financial disclosure, fair terms, and careful drafting are what make one of these agreements hold up. If you’re considering a postnuptial agreement, or you already have one you’d like reviewed under the new law, our attorneys can help you put it on solid ground.
Sally M. Colton
Certified Family Law Specialist and former Judge Pro Tempore dedicated to personalized, compassionate representation in divorce and custody matters.
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