Most people have heard of a prenuptial agreement and assume the postnuptial version is the same document signed later. It is not, and the difference is not cosmetic. Florida has a statute governing premarital agreements. That statute does not apply to agreements signed after the wedding. Postnuptial agreements are evaluated under a separate body of case law, and on the question of financial disclosure they are held to a stricter standard than prenups are. Here’s why couples sign them, what governs whether they hold up, and what they cannot accomplish no matter how carefully they are drafted.
What a Postnuptial Agreement Is
A postnuptial agreement is a contract between spouses, entered after the marriage has already begun, addressing how property, debts, and support would be handled if the marriage ends by divorce or death.
Signing one is not a prediction that the marriage will fail. In practice most postnups are signed by couples who intend to stay together and want a specific financial question settled rather than left open. The agreement functions the way any contract does — it replaces uncertainty with terms both people negotiated while on good terms.
The Statute That Does Not Apply
Florida Statute 61.079 is the Uniform Premarital Agreement Act. Its own definition limits its reach: a premarital agreement means an agreement between prospective spouses made in contemplation of marriage and to be effective upon marriage.
Prospective spouses. Once you are married, you are no longer prospective, and the statute no longer describes your situation. That single definitional line is why postnuptial agreements sit outside the statutory framework entirely.
The statute also states that a premarital agreement is enforceable without consideration other than the marriage itself. A postnuptial agreement cannot rely on that, because the marriage already happened. Ordinary contract principles apply instead, which is one of several reasons these agreements need to be drafted with more care rather than less.
The Framework That Does Apply
Florida courts evaluate postnuptial agreements under general contract principles and the case law developed for marital agreements, principally Casto v. Casto, decided by the Florida Supreme Court in 1987, and the earlier decision in Del Vecchio v. Del Vecchio.
Under that framework, an agreement can be set aside on either of two grounds. One concerns the circumstances of execution — whether the agreement was the product of fraud, deceit, duress, coercion, misrepresentation, or overreaching. The other concerns the substance and the information available when it was signed, examining whether the agreement is unreasonable and whether there was adequate knowledge of the other spouse’s finances.
Disclosure Is the Sharper Difference
Here is the part that surprises people who researched prenups first. Florida does not require full financial disclosure for a premarital agreement to be enforceable. Under 61.079, a prenup can survive incomplete disclosure unless it was unconscionable when executed and the challenging party lacked adequate knowledge and did not waive disclosure in writing.
Postnuptial agreements are treated with more scrutiny on exactly this point. Where spousal rights are being waived, fair disclosure of the other spouse’s estate matters, and courts examine it closely.
The practical takeaway is that skimping on disclosure is the most common way a postnup fails later. Complete schedules of assets, debts, income, and business interests, exchanged and attached to the agreement, are not optional formalities. They are the primary defense against a challenge years down the road.
Why Couples in Miami Sign Them
The reasons cluster into a few recognizable situations.
A Business That Grew During the Marriage
Someone starts a company after the wedding. It succeeds. Now a substantial marital asset exists whose value depends on one spouse continuing to run it, and dividing it in a divorce would be genuinely difficult. A postnup can establish in advance how the business is valued and what the other spouse receives instead of an ownership interest, which protects both people and often protects the company itself.
An Inheritance or a Financial Reset
Inherited property starts as non-marital, but the line blurs quickly once marital funds or joint accounts touch it. A postnup can document the parties’ intentions before that happens. Similarly, couples who reconcile after a separation frequently want the financial terms of that reconciliation written down, and a postnup is the instrument for it.
Couples also use them when one spouse leaves the workforce to raise children, to address the economic consequences of that choice while both people still agree about what it is worth.
What a Postnuptial Agreement Cannot Do
Some things are outside the reach of any marital agreement in Florida.
Child support belongs to the child, not to the parents, and cannot be eliminated or reduced by agreement. Custody and time-sharing cannot be predetermined either, because those are decided on the best interests of the child at the time the question is actually before a court, not on terms two adults negotiated years earlier.
An agreement that overreaches into these areas does not simply fail on those provisions. It invites a broader challenge to the whole document.
Building One That Holds Up
The elements that survive scrutiny are consistent. Complete, documented financial disclosure exchanged before signing. Independent counsel for each spouse, or a clear, knowing, written waiver by anyone who declines it. Time to review, without a signing deadline that looks like pressure. Terms that are not so lopsided they invite the argument that something was wrong with the process.
Every one of those elements exists to answer a question a court might ask later. An agreement signed quickly, with one lawyer, and vague financial attachments is an agreement someone will challenge, and the challenge will have material to work with.
Getting the disclosure and the process right at the outset is what determines whether a postnuptial agreement does its job years later, and it is where our team at Reynoso Erickson Trial Law, P.A. spends its time on these documents.