Can You Get a Prenup After Getting Married in Florida?

It is one of the most common questions Florida family law attorneys hear: "We forgot to get a prenup before the wedding — can we still get one?" The short answer is no. Florida law defines a prenuptial agreement as a contract entered into before marriage. Once you are married, a prenup is off the table. But there is an alternative: the postnuptial agreement.

This post explains the legal distinction between prenuptial and postnuptial agreements in Florida, the statutes and case law that govern each, and what married couples should know before pursuing a postnuptial agreement.

What Florida Law Says About Prenuptial Agreements

Florida's Uniform Premarital Agreement Act, codified at Fla. Stat. § 61.079, defines a "premarital agreement" as an agreement between prospective spouses made in contemplation of marriage and effective upon marriage. The statute is explicit: the agreement must be executed before the marriage takes place.

Under § 61.079(3), a premarital agreement must be in writing, signed by both parties, and is enforceable without consideration other than the marriage itself. The marriage is the consideration. Once the marriage has occurred, that specific legal mechanism is no longer available to the parties.

This is not a mere technicality. The timing requirement reflects the legislature's intent that both parties negotiate the terms of their financial arrangement while they still have the ability to decide whether to proceed with the marriage. That bargaining dynamic changes fundamentally once the couple is already married.

What Is a Postnuptial Agreement?

A postnuptial agreement — sometimes called a "postnup" or "postmarital agreement" — is a contract between spouses that is executed after the marriage has taken place. Like a prenuptial agreement, a postnup addresses the division of property, spousal support, and other financial matters in the event of divorce.

Unlike prenuptial agreements, postnuptial agreements are not governed by a specific Florida statute. There is no Florida equivalent to § 61.079 for postnuptial agreements. Instead, Florida courts evaluate postnuptial agreements under general contract law principles and relevant case law.

Florida Case Law on Postnuptial Agreements

The leading Florida case on postnuptial agreements is Casto v. Casto, 508 So. 2d 330 (Fla. 1987). In Casto, the Florida Supreme Court held that postnuptial agreements between spouses are enforceable but subject to heightened scrutiny compared to ordinary contracts. Because spouses occupy a confidential relationship, the court requires a greater showing of fairness and full disclosure.

Under the Casto framework, a postnuptial agreement may be set aside if a challenging party can demonstrate that the agreement was the product of fraud, duress, coercion, or overreaching. The court also looks at whether both parties received full and fair disclosure of the other's financial circumstances before signing.

Subsequent decisions have reinforced the enforceability of marital agreements. In Hahamovitch v. Hahamovitch, 174 So. 3d 983 (Fla. 2015), the Florida Supreme Court held that broad prenuptial language waiving each spouse’s interest in the other’s separately titled property can be enforceable even when those assets appreciated through marital effort. The case underscores Florida courts’ willingness to uphold clear contractual provisions in marital agreements.

Key Differences Between Prenuptial and Postnuptial Agreements

While both prenuptial and postnuptial agreements address similar subjects — property division, alimony, and financial rights — there are important legal differences between the two.

• Governing law. Prenups are governed by Fla. Stat. § 61.079. Postnups are governed by general contract law and case law, primarily Casto v. Casto.
• Consideration. For a prenup, the marriage itself is sufficient consideration. For a postnup, because the marriage has already occurred, the agreement generally requires independent consideration — a mutual exchange of promises or some other bargained-for benefit.
• Standard of review. Postnuptial agreements face heightened judicial scrutiny. Courts examine them more carefully because the confidential relationship between spouses creates a greater risk of undue influence.
• Burden of proof. Under § 61.079(7), the party challenging a prenup bears the burden of proving grounds for unenforceability. With postnups, Florida courts may place a greater burden on the party seeking to enforce the agreement to demonstrate fairness.
• Statutory protections. The specific procedural safeguards in § 61.079 — including the detailed provisions regarding voluntariness and financial disclosure — apply only to prenuptial agreements.

Why Couples Seek Postnuptial Agreements

There are many reasons a married couple might want a postnuptial agreement. Some couples simply did not get around to signing a prenup before the wedding. Others experience significant financial changes during the marriage — a new business, an inheritance, a dramatic increase or decrease in income — that make a formal financial agreement prudent.

Postnuptial agreements are also used when a marriage has experienced difficulty and the couple wants to establish clear financial expectations as part of a reconciliation. In some cases, one spouse has engaged in financial misconduct, and a postnup provides a framework for moving forward with transparency.

Whatever the reason, it is important to understand that a postnuptial agreement is not simply a late prenup. The legal requirements are different, the standard of review is more demanding, and the enforceability analysis can be more complex.

What Can a Postnuptial Agreement Cover?

A postnuptial agreement can address many of the same subjects as a prenuptial agreement. Common provisions include the identification and division of marital and non-marital property, the waiver or limitation of alimony, the treatment of business interests, the allocation of debts, and the disposition of specific assets such as real estate or retirement accounts.

However, like prenuptial agreements, postnuptial agreements in Florida cannot adversely affect the rights of minor children. Provisions regarding child custody and child support are subject to judicial review and must meet the best-interests-of-the-child standard regardless of what the parties have agreed.

Steps to Protect the Enforceability of a Postnuptial Agreement

Because postnuptial agreements face heightened scrutiny in Florida courts, careful drafting and execution are essential. The following steps can help protect enforceability:

1. Full financial disclosure. Both spouses should provide complete and accurate financial disclosures, including income, assets, liabilities, and expenses. Incomplete or misleading disclosures are among the most common grounds for invalidating a postnup.
2. Independent legal counsel. Each spouse should retain his or her own attorney. While not strictly required, the absence of independent counsel can be evidence that one party did not fully understand the agreement or was subject to undue influence.
3. Voluntariness. The agreement must be entered into voluntarily by both parties. Any evidence of coercion, pressure, or duress can render the agreement unenforceable.
4. Substantive fairness. A postnup that is grossly one-sided may be set aside. Courts look at whether the terms were fair and reasonable at the time of execution.
5. Proper execution. The agreement should be in writing, signed by both parties, and ideally notarized. Some attorneys recommend having the signing witnessed.

Can You Convert a Postnup Into a Prenup?

No. The legal categories are distinct. A postnuptial agreement cannot be retroactively classified as a prenuptial agreement. The timing of execution determines which legal framework applies. An agreement signed after the marriage is a postnuptial agreement, regardless of what the parties call it or when they began negotiating its terms.