Postnuptial agreements, sometimes called “marital agreements,” may feel like a new relationship tool for modern couples juggling careers, businesses, and blended families. Yet their legal roots go back centuries, tracing the evolution of property law, shifting gender roles, and evolving views of marriage itself. In many ways, the history of postnuptial agreements mirrors the transformation of marriage itself: from a single legal identity to a true partnership of equals. Historically, couples weren’t always free to craft their own marital contracts. And even today, not every state enforces postnuptial agreements. Read on to explore the history of postnups and discover how they became a tool for modern couples.
The early years: When postnups were impossible
The first major obstacle to postnuptial agreements came from English common law, which heavily shaped early American law. Under the doctrine of “coverture,” a married woman’s legal identity was essentially absorbed into her husband’s. She could not own property in her own name, enter into contracts independently, or sue and be sued. This meant postnuptial agreements, contracts between spouses, were impossible in practice and theory. The reasoning was straightforward: you can’t make a binding contract with yourself. In the eyes of the law, husband and wife were one person, and that person was the husband.
Cracks in the foundation: women’s property rights
By the mid-19th century, reform movements began chipping away at the strictures of coverture. Mississippi led the way in 1839, followed by New York in 1848, with the passage of the Married Women’s Property Acts. These laws gave married women the right to own property, control their earnings, and enter into contracts in their own names. Over the next several decades, every state enacted some version of these protections, though the scope and strength of the laws varied widely. These property rights reforms didn’t automatically create postnups, but they laid the legal groundwork. Once spouses were recognized as separate legal entities, the theoretical possibility of enforceable marital contracts finally emerged.
The mid-20th century: divorce reform and the seeds of postnup recognition
Even after property laws evolved, most states remained cautious about postmarital agreements that could alter marital rights. Courts feared such contracts might encourage divorce or enable one spouse to take advantage of the other. That skepticism began to shift in the 1960s and 1970s, when the no-fault divorce movement swept across the United States. California led the way in 1969, and by the mid-1980s, every state offered some form of no-fault divorce. This cultural and legal transformation reframed marriage, from a rigid, lifelong contract to a partnership that could adapt, or dissolve, without proving fault. As divorce lost much of its stigma, courts and legislatures began to view postnups not as threats, but as tools to promote stability, clarify financial expectations, and reduce conflict if a marriage ended.
The 1980s and 1990s: prenup influence and early precedent
In the same era, prenuptial agreements gained wider acceptance, helped in large part by the Uniform Premarital Agreement Act (UPAA) in 1983. While the UPAA didn’t directly govern postnups, it established clear principles for enforceability of prenups, such as voluntary execution, full financial disclosure, and protection against unconscionable terms. These standards would go on to heavily influence how courts later evaluated postnuptial agreements.
Meanwhile, case law from the late 20th century began cautiously embracing and recognizing postnups. In 1976, the California Supreme Court upheld a premarital agreement while suggesting that agreements made during marriage could also be enforceable if fair (In re Marriage of Dawley (1976)). Other states followed suit, often in cases involving couples reconciling after marital difficulties, where postnups were used to resolve disputes and encourage the marriage to continue.
Fiduciary duty: why postnups face higher scrutiny
A key difference between prenups and postnups is timing: postnups are created after marriage, when spouses already owe each other a fiduciary duty. In states like California, that duty is legally comparable to the loyalty and fairness expected between business partners. Unlike arm’s-length contracts between unrelated parties, postnuptial agreements are subject to close judicial scrutiny. Courts may invalidate a postnup if one spouse concealed assets, pressured the other into signing, or otherwise failed to act in good faith. This heightened scrutiny is one reason why postnups evolved more slowly than prenups. For this reason, many couples involve attorneys for both spouses when drafting a postnup.
The 21st century: state-by-state adoption
Today, nearly every U.S. state recognizes postnups in some form, though the rules vary significantly:
- Massachusetts famously adopted the “two-look” doctrine in the 2010 case, Ansin v. Craven-Ansin. Under this doctrine, courts review postnups for fairness both at the time of signing and at enforcement.
- Florida, Texas, and Connecticut explicitly recognize postnups applying standards similar to prenups but with extra emphasis on full financial disclosure and fairness (Fla. Stat. § 61.079).
- California holds postnups to a fiduciary duty standard, requiring “the highest good faith and fair dealing (Cal. Fam. Code § 721).
- Ohio, recently as of 2023, officially recognizes and enforces postnuptial agreements (Ohio Rev. Code § 3103.06).
- Nebraska and Iowa are a few of the states that are still restrictive about postnups. Nebraska courts historically view them as contrary to public policy unless tied to separation, and Iowa courts often refuse to enforce them even in separation cases.
These variations mean that couples moving across state lines, or with assets in multiple states, need careful legal drafting. Consulting an experienced family law attorney is critical to fully understanding the nuanced rules in your state. Attorneys also monitor ongoing legal developments, as courts regularly revisit postnup validity and fairness, especially given the fiduciary duties spouses owe each other.
While the U.S. experience is unique, postnups actually exist worldwide. In England, they were historically unenforceable until the landmark Radmacher v. Granatino decision in 2010, which gave “decisive weight” to marital agreements deemed fair. Some civil law countries, like France, have long allowed spouses to alter marital agreements after marriage, influencing American thinking about flexibility. Couples planning to live or hold assets abroad should consult attorneys familiar with international postnuptial laws. Careful planning, full disclosure, and fairness remain the cornerstones of a postnuptial agreement that courts are likely to uphold.
Lifestyle clauses and modern trends
Today’s postnups go beyond dividing property. Some include lifestyle clauses, addressing issues such as where children will be educated or how a family business will be managed. While certain clauses can be enforceable in limited contexts, many courts refuse to enforce provisions that interfere with child custody or public policy.
Another modern trend is the rise of reconciliation agreements, in which spouses facing divorce agree to specific terms in an effort to save the marriage. Essentially a subtype of postnuptial agreement, these agreements are gaining recognition in many states, reflecting the evolving ways couples use postnups to manage both finances and family life.
Final word on the history of prenups
The evolution of postnuptial agreements traces a remarkable journey, from being impossible under coverture, to cautious acceptance, to widespread recognition with careful safeguards. As society continues to change, with more couples marrying later in life, blending families, or managing joint businesses, the demand for postnups is likely to grow. Yet, their enforceability will always hinge on the state’s laws, the fairness of the terms, and the care taken in drafting. Postnups have become an established tool in modern marriage planning, but they have earned that place through nearly two centuries of legal and social evolution and transformation.
Katherine (Kathy) Bakes is the founder and managing attorney of Bakes Law LLC. Her eleven years of practice involves all aspects of family law, including the formation of prenuptial and postnuptial agreements, divorce and legal separations, child custody, child support, and visitation agreements, spousal support and financial settlements. Kathy also engages in the practice of estate planning including the formation of wills, revocable and irrevocable trusts, durable powers of attorney, health care proxies, HIPAA authorizations and living wills. Kathy is a member of both the Connecticut and Massachusetts state bars after receiving her Juris Doctorate degree from New England Law | Boston. Kathy lives in Southport, CT with her husband and toddler. Outside the office, Kathy enjoys playing the piano and teaches music education to students of all ages.
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