Florida Postnuptial Agreements

A postnuptial agreement is a written contract between spouses, signed after the marriage, that defines how property, debts, and alimony will be treated if the marriage ends. Unlike a prenuptial agreement -- which is governed by the Uniform Premarital Agreement Act -- a Florida postnup is evaluated under common law contract principles, with the additional layer of the fiduciary relationship between spouses.

When a Postnup Makes Sense

Couples often turn to postnuptial agreements when life events have changed the assumptions of the marriage. Common scenarios include:

One spouse has launched, acquired, or inherited a business that the couple wants to keep separate
An inheritance has been received that the couple wants to preserve as nonmarital
One spouse plans to stop working to raise children, and both want to predefine the financial consequences
The couple has overcome a serious marital problem and wants to set ground rules for what happens if a similar problem recurs
A spouse who would have signed a prenup but ran out of time before the wedding

Enforceability Standard

Florida courts evaluate postnups under the framework summarized in Casto v. Casto, 508 So. 2d 330 (Fla. 1987), and refined in later decisions. A postnup may be set aside if:

It was reached through fraud, deceit, duress, coercion, misrepresentation, or overreaching, or
It makes an unfair or unreasonable provision for the challenging spouse, given the circumstances of the parties

If the challenger meets the threshold of unfairness, a presumption arises that the agreement was the product of inadequate financial disclosure or inadequate knowledge of the other spouse's resources. The proponent of the postnup then has the burden to show that the challenger had general and approximate knowledge of the other spouse's assets and income before signing.

Best Practices for an Enforceable Postnup

Separate, independent attorneys. Especially important for postnups, where the fiduciary relationship between spouses heightens the risk of overreach.
Full written financial disclosure. A schedule of all assets, debts, and income, supported by current tax returns and statements.
Adequate time between presentation and signature. No ambush signings.
Substantive fairness. Terms that completely disinherit one spouse after a long marriage are far more likely to be set aside than a balanced division.
Consideration. The continuation of the marriage is typically the consideration; however, courts also examine whether each spouse received something of value in the agreement itself.

What a Postnup Cannot Do

A postnup -- like a prenup -- cannot waive a child's right to support or bind the court's future best-interest analysis of time-sharing. Any provision that attempts to do so is unenforceable. Provisions waiving alimony are enforceable when the agreement otherwise meets the validity standards.

The Different Legal Framework for Florida Postnups

A Florida postnuptial agreement is not governed by the Uniform Premarital Agreement Act. Section 61.079 applies only to agreements signed in contemplation of marriage. Postnups are governed by Florida common law, principally Casto v. Casto, 508 So. 2d 330 (Fla. 1987), and a long line of progeny including Macar v. Macar, 803 So. 2d 707 (Fla. 2001), Petracca v. Petracca, 706 So. 2d 904 (Fla. 4th DCA 1998), and the more recent cases that apply the Casto framework to modern facts. Where estate-planning rights such as the elective share are waived in the postnup, Florida Statutes § 732.702 also applies and imposes its own execution requirements.

The difference matters in practice. Under the Premarital Act, a challenger must overcome the statutory enforcement test of § 61.079(7). Under Casto, the inquiry is judge-made and is framed as a two-part analysis with shifting burdens. The standards overlap in important ways -- disclosure, voluntariness, and substantive fairness appear in both -- but the postnup analysis layers an additional concern: spouses owe each other a duty of good faith and fair dealing that a court will not assume between two people who are merely engaged.

Heightened Scrutiny Because of the Confidential Relationship

Florida courts treat married persons as parties to a confidential relationship. The wealthier or more financially sophisticated spouse cannot rely on the other spouse's inattention or trust to extract a one-sided agreement. The proponent of a postnup carries a heavier persuasion burden than the proponent of an arm's-length commercial contract. Where one spouse handles the family finances and the other does not, the court will look closely at whether the financially involved spouse used that informational advantage to obtain terms the other spouse did not truly understand.

The Casto Two-Part Test

Under Casto v. Casto, a postnuptial agreement (and a separation agreement signed during marriage) may be set aside on either of two independent grounds.

First Ground: Fraud, Deceit, Duress, Coercion, Misrepresentation, or Overreaching

If the challenging spouse proves that the agreement was the product of any of these defects in the process, the agreement may be set aside without inquiry into the substantive fairness of its terms. Overreaching includes situations in which one spouse used a position of dominance, confidence, or financial control to obtain terms the other spouse would not have accepted with full understanding.

Second Ground: Unfairness or Unreasonableness Combined With Disclosure Failure

If the challenging spouse proves that the agreement makes an unfair or unreasonable provision for that spouse, given the circumstances of the parties, a presumption arises that the agreement was reached without full and frank disclosure or without adequate knowledge of the other spouse's resources. The burden then shifts to the proponent to overcome that presumption by showing one of two things: that the challenging spouse had a general and approximate knowledge of the character and extent of the other spouse's resources at the time of signing, or that there was full, fair, and open disclosure before signing.

Either path -- knowledge or disclosure -- combined with voluntary execution will preserve the agreement. A postnup that is substantively reasonable rarely reaches the second prong at all, because the challenger cannot get past the threshold finding of unfairness.

When a Florida Postnup Makes Sense

Couples turn to postnuptial agreements in a range of circumstances. The legitimacy of the reason often correlates with how the agreement is later perceived by a court reviewing it.

Reconciliation After Separation

When spouses have separated, retained counsel, and begun negotiating divorce terms, and then decide to reconcile, a postnup that memorializes their understanding can stabilize the marriage. These agreements often address what will happen if a future separation occurs and what financial steps the spouses are taking to rebuild trust.

Business Formation or Acquisition During Marriage

One spouse may be about to start a company, take on outside investors, or acquire a substantial business interest. Investors and lenders frequently require a postnup that confirms the non-owner spouse's claims will not interfere with the enterprise. The postnup typically defines the business and successor entities as separate property and addresses how marital labor will be compensated through salary.

Inheritance About to Be Received

Inherited property is presumptively nonmarital under Florida Statutes § 61.075(6)(b), but commingling and active appreciation can convert it. When a substantial inheritance is on the horizon, a postnup can clearly delineate how the inheritance and its income will be held and managed.

Financial Restructuring

Refinancing the marital home, transferring property between spouses for asset-protection or estate-planning reasons, or rebalancing accounts after a windfall can all trigger interspousal transfers that warrant a postnup to clarify the parties' intentions.

Alimony and Support Clarification

A postnup can define the categories and amounts of alimony each spouse will pay or waive if the marriage ends. As with prenups, the waiver of all support that would leave a spouse eligible for public assistance is subject to public-policy limits.

A Prenup That Did Not Get Signed in Time

Couples who ran out of time before the wedding sometimes execute the agreement they had been negotiating as a postnup. The substantive terms can be very similar, but the legal framework changes the day after the ceremony.

Typical Clauses

Identification of separate property each spouse brought to the marriage, with attached schedules
Treatment of appreciation, income, and reinvestment of separate property
Allocation of debts incurred before and during the marriage
Alimony provisions, including waivers, caps, or formulas
Life insurance and beneficiary obligations
Estate-planning waivers, including elective share, family allowance, intestate share, pretermitted-spouse rights, and homestead to the extent waivable
Confidentiality and non-disparagement clauses
Choice-of-law and forum-selection clauses
Severability so that the failure of any one provision does not collapse the rest of the agreement

Required Elements for Enforceability

Drawing the threads together, a Florida postnup that is most likely to be enforced will include all of the following:

Full and fair financial disclosure. Attached schedules of assets, liabilities, and income, supported by tax returns and statements, dated and signed.
Voluntary execution. Each spouse signs free of coercion, with adequate time to review, ideally after the kind of measured negotiation that the record can demonstrate.
Substantive fairness. Terms that, viewed as a whole, are not unconscionable and that leave each spouse with something meaningful in the event of divorce or death.
Independent counsel for each spouse. Not legally required, but practically essential. The proponent should not allow the other spouse to proceed unrepresented, and the agreement should recite that each party had the opportunity to consult separate counsel and either did so or knowingly declined.
Proper execution formalities. Two subscribing witnesses are required by Florida Statutes § 732.702 for any waiver of elective share or other death-related rights. Notarization is recommended as a matter of practice even though not required for ordinary contract enforcement.

Common Mistakes That Defeat a Postnup

Signing Under Threat of Separation or Divorce

The most frequent attack on a postnup is duress. If one spouse presents the agreement as the price of preserving the marriage -- "sign this or I file" -- the other spouse will later argue that consent was not voluntary. Florida courts distinguish between hard bargaining (acceptable) and coercion (not acceptable), and the line is drawn case by case. The record matters: contemporaneous emails, text messages, and counsel communications either support or refute the duress claim.

Inadequate Disclosure

Omissions from the financial schedules are common ground for challenge. A spouse who fails to disclose a substantial bank account, an interest in a closely held entity, or a contingent inheritance invites the Casto presumption. The cure is not perfection but reasonable and good-faith disclosure, documented in writing.

Same Lawyer for Both Spouses

Joint representation in the drafting of a postnup creates serious conflict-of-interest issues and weakens the agreement's defenses. A spouse who later argues she did not understand what she was signing finds a sympathetic court when the only lawyer in the room represented the other side.

Last-Minute Ambush

Presenting the agreement at a notary's office for immediate signature, without prior review, defeats voluntariness as surely in the postnup context as in the prenup context.

Failure to Update

A postnup signed in the second year of the marriage may not fit the circumstances of the twentieth. Couples who want continued protection should consider periodic amendments.

Modification and Revocation

A Florida postnuptial agreement may be modified or revoked only by a subsequent written agreement signed by both spouses. Conduct alone does not revoke it. A handwritten side note initialed by one spouse is unlikely to satisfy contract-formation requirements. If the parties later sign a Marital Settlement Agreement in connection with a divorce, the MSA will typically supersede the postnup with respect to the issues it addresses, but a well-drafted postnup may already control many of the same issues, and inconsistencies between the two documents can become litigation flashpoints.

Interaction With a Subsequent Prenup-Like Document

Once a couple is married, no later agreement is a "prenup" -- the marriage has already occurred. Couples who attempt to redraft their existing prenup after the wedding should treat the new document as a postnup, analyzed under Casto, and should not rely on the original Premarital Act framework to defend the substituted agreement.

Marital Settlement Agreements vs. Postnuptial Agreements

A postnuptial agreement is not the same as a Marital Settlement Agreement (MSA). A postnup is signed while the spouses are married and intend to remain so. An MSA is signed in contemplation of dissolution and is filed with the court in an active divorce case. The MSA is incorporated into the final judgment under Florida Statutes § 61.075(3) and is enforced as a court order, not just as a contract. Enforcement of an MSA generally invokes the court's contempt power and the array of post-judgment remedies available in family-law cases. Enforcement of a postnup, by contrast, is typically a separate breach-of-contract claim or a defense raised when divorce is filed.

The standards for setting aside an MSA are also slightly different. The Florida Supreme Court in Macar v. Macar distinguished between MSAs reached during pending litigation and postnups reached during an intact marriage, applying a somewhat narrower set of grounds for challenging an MSA. The takeaway is that timing matters: the same set of words can be analyzed under different rules depending on when it was signed and whether litigation was pending.

How an Attorney Adds Value

Postnups are deceptively simple to write and deceptively easy to lose. Effective representation includes structured negotiation between separately retained lawyers, complete and contemporaneous financial disclosure, careful drafting that anticipates likely attacks on the agreement, and execution practices that build the record needed to defend the document years later. Whether you are considering a postnup to protect a business, to confirm an inheritance, to stabilize a reconciliation, or to update an outdated premarital agreement, the process is at least as important as the terms.

Call 786-522-1411 to draft or review a Florida postnuptial agreement.