Yes, You’ve Already Got a Prenup

Every married couple has a prenup. The only question is whether you wrote it yourself or accepted the one your state wrote for you.

Key Takeaways

• A prenup is a set of rules governing your financial life during marriage and, if it comes to it, after. Getting married without a prenup does not mean you have no prenup — it means you have accepted your state’s default version.
• The default prenup was largely written in the 1800s. It does not account for how modern couples actually live.
• Under the default rules, title no longer determines ownership after marriage. Your paycheck, and everything it touches, becomes marital property.
• A customized prenup replaces the state’s one-size-fits-all rules with your own — defining what is mine, yours, and ours based on your actual financial lives.

You Are Already Under Contract

When you sign a marriage license, you are signing a contract. Most people understand that intuitively — marriage is a legal relationship, not just a personal one. What most people do not realize is that by signing that license without a prenuptial agreement in place, they are also accepting a second contract: the set of state laws that will govern their finances for the duration of the marriage, and determine how everything gets divided if it ends.

This is what attorneys mean when they refer to the “default prenup.” It is not a document anyone hands you. It is the body of state marital law that applies automatically to every married couple that has not opted out of it with their own agreement. You did not negotiate it. You almost certainly have not read it. But the moment you said “I do,” you agreed to it.

The question is not whether you have a prenup. You do. The question is whether you wrote it.

What the Default Prenup Actually Says

The foundational rules of state marital law were largely drafted in the 1800s. They have been updated in various ways over the decades, but the core structure reflects a vision of marriage that has almost nothing in common with how couples live today.

Here is the central rule: once you are married, the name on an account or a piece of property no longer determines who owns it. Your entire life before marriage, you operated under a simple and obvious assumption — if your name is on it, it is yours; if your name is not on it, it is not yours. That is how every other legal and financial relationship in your life works. The default prenup sets that assumption aside.

Under the default rules, your paycheck becomes marital money the moment it is earned. Everything you buy with that paycheck becomes marital property. Everything that paycheck touches — your checking account, your retirement fund, your car loan, your condo mortgage, your brokerage account — gets commingled with marital funds. The assets you owned individually before the wedding begin losing their separate status, and the legal mechanism for proving what was yours going in becomes increasingly difficult with every passing year.

The default prenup does not ask whether this reflects your intentions. It applies regardless.

Why Nobody Would Choose It Voluntarily

Consider the choice directly. Two contracts are sitting in front of you. One is the default prenup — the state’s version, written over a century ago, applying uniform rules to your financial life without regard to what you actually own, what you actually intend, or how you actually plan to live. The other is a customized agreement that you and your spouse negotiate together, reflecting your real financial picture and your real intentions.

Nobody picks the default.

The default made reasonable sense for a specific historical context: couples marrying young, starting from nothing, building an entire financial life together from scratch. If you are getting married at twenty with fifty dollars to your name, throwing everything into one shared bucket is not much of a sacrifice.

That is not most couples today. By the time most people get married now, each person has been managing their own finances for a decade or more. There are bank accounts, retirement funds, a car, credit cards, student loans, maybe equity in a home, maybe ownership in a business. Two people with that much financial history are not starting from scratch — they are merging two established financial lives. The default prenup treats that merger as if none of that prior history matters. A customized prenup treats it the way both parties actually intend.

The Three Buckets the Default Ignores

Most married couples, if they are honest about how they actually live, do not treat their finances as entirely joint. There are things that are clearly mine — a car, a phone, a retirement account from a previous employer, a wardrobe, an inheritance that may arrive someday. There are things that are clearly yours. And there are things that are genuinely shared — the joint checking account, the mortgage, the vacation fund, the investment accounts you build together.

These three buckets — mine, yours, and ours — are how modern couples actually think about money. The default prenup collapses them into one. It treats the phone in your pocket and the retirement account you have been contributing to since your mid-twenties the same way it treats the joint savings account you opened together: all of it is marital property, all of it is potentially subject to division.

A customized prenup draws the lines where you and your spouse actually want them drawn. It does not have to mean keeping everything separate. It does not have to be adversarial. It simply means that the boundaries between mine, yours, and ours are documented, agreed upon, and legally enforceable — rather than defaulting to a set of rules that did not anticipate your situation and does not reflect your intentions.

Opting Out Is the Point

A prenup is, at its legal core, an opt-out mechanism. It is the tool the law provides for couples who want to replace the state’s default rules with their own. Every state recognizes this. Courts consistently enforce valid prenuptial agreements precisely because the law treats the choice to have one as a legitimate exercise of both parties’ autonomy.

What a prenup says is: we have read the default contract, we understand what it would apply to us, and we have chosen different terms. That opt-out is not a signal of distrust or a prediction of failure. It is the exercise of two adults making an informed decision rather than drifting into a contract they never agreed to.

You are signing a contract either way. One was written for you, by people who lived in a different century, for a version of marriage that no longer exists. The other one you write yourself.

Frequently Asked Questions

If I don’t sign a prenup, what rules actually govern my marriage? The marital property laws of the state that has jurisdiction over your marriage and any eventual divorce. These rules determine what counts as marital versus separate property, how assets are divided, and how debts are allocated. They vary meaningfully from state to state, and most people have never read them.

Can a prenup truly replace state law? Yes. A valid prenuptial agreement supersedes the state’s default marital property rules. Courts consistently uphold prenups as binding contracts, and treat them as the governing document for any financial matters the agreement addresses. The state’s default rules only apply to issues the prenup does not cover.

Does having a prenup mean we are planning to divorce? No more than having car insurance means you are planning to crash. A prenup establishes the financial framework for your marriage. Most of the value it provides shows up during the marriage — in clarity, reduced financial conflict, and a documented understanding of what belongs to each spouse. The divorce protection is part of the package, but it is not the reason most couples get one.

What if we want the default rules to apply — is that a valid choice? It is a valid choice if it is made deliberately. The issue is that most couples who end up under the default rules did not actively choose them — they simply did not get a prenup. If you have reviewed your state’s marital property rules and concluded they reflect your actual intentions, you can proceed without an agreement. But that review should happen before the wedding, not during a divorce.

Is a postnup the same thing if we missed the window before the wedding? A postnuptial agreement carries the same legal force as a prenup and can address the same financial questions. The process is somewhat more complex because both parties are already legally married, which changes the negotiating dynamic. But if you are already married and have not addressed ownership and division, a postnup is the next best option and is far better than relying on the default.