Do You Need a Prenup for Common-Law Marriage or a Domestic Partnership?

Short answer: It depends on whether the law treats your relationship as a marriage. If you live in one of the few states that still recognizes common-law marriage and you meet that state's requirements, you are legally married — and a prenuptial agreement can work for you the same way it works for any couple. If you are in a domestic partnership or simply living together, a traditional "prenup" usually does not fit, because a prenup is a contract that takes effect when you marry. Instead, you typically use a cohabitation agreement or a domestic partnership agreement. The rules vary sharply from state to state, so the right document depends on where you live.

First, get the labels straight

People use "common-law marriage," "domestic partnership," and "cohabitation" interchangeably in conversation, but the law treats them very differently. Choosing the wrong document is one of the most common and expensive mistakes couples make.

Common-law marriage = a real marriage (in a handful of states)

A common-law marriage, where it exists, is a legally valid marriage created without a license or ceremony. Only a small number of states still allow new common-law marriages to form, and each sets its own test — typically some combination of (1) both partners being legally free and intending to be married, (2) living together, and (3) holding yourselves out publicly as a married couple. Simply living together for a certain number of years is not enough by itself; there is no nationwide "seven-year rule."

This matters enormously. If your state recognizes your common-law marriage, you are married for nearly all purposes — property, debts, inheritance, and divorce. That means if you split up, you go through an actual divorce, with the same property division your state applies to any other married couple.

Domestic partnership = a separate legal status (not the same as marriage)

A domestic partnership is a status created by a state, county, or city through registration. What it gives you — hospital visitation, employer benefits, inheritance rights, or something broader — depends entirely on the jurisdiction that created it. Some partnerships carry nearly all the rights of marriage; others are narrow. Because a domestic partnership is generally not a marriage, the marriage-based prenup statutes usually do not govern it.

Cohabitation = living together with no special status

If you live together but are not married and not registered, you are, in the eyes of most courts, two individuals who happen to share a home. Without a written agreement, you generally have no automatic claim to each other's property or income if you separate.

Do you need a prenup for a common-law marriage?

If you are genuinely common-law married — or you are about to meet your state's requirements — then yes, a prenuptial agreement can be worth it for the same reasons any couple considers one: to decide in advance how property and debt would be divided, to protect a business or premarital assets, to clarify what stays separate, and to spare yourselves a contested fight later.

There is a timing wrinkle, though. A prenuptial (premarital) agreement is signed before the marriage exists. Common-law marriage is tricky precisely because there is often no clear wedding date — the marriage forms gradually as you meet the criteria. If a court later decides you were already common-law married when you signed, the document may be analyzed as a postnuptial agreement (signed during marriage) rather than a prenup. Postnups are enforceable in many states but are sometimes held to stricter fairness standards. Because this turns on your specific state's law and facts, this is exactly the kind of issue to confirm locally before you rely on the agreement.

Across states, courts generally enforce marital agreements only when they are in writing and signed, entered into voluntarily (no fraud, duress, or coercion), and not unconscionable. Many states also expect fair financial disclosure — each partner showing the other a reasonable picture of assets and debts — although a partner can usually waive disclosure in a clear written statement. The exact standard, and whether you each need separate lawyers, varies by state.

Do you need a prenup for a domestic partnership?

Usually you do not need a "prenup" in the technical sense, because the marriage-based prenup laws may not apply to a partnership. But you very likely do want a written agreement — just one built for your status:

• Domestic partnership agreement: If your state or city's partnership carries marriage-like property rights, an agreement can set out how property and debt are handled, much like a prenup does for spouses.
• Cohabitation agreement: If your partnership is narrow, or you are simply living together, a cohabitation agreement is the standard tool. It is a private contract covering who owns what, how shared expenses and property are split, and what happens if you separate.

The label matters less than matching the document to how your jurisdiction treats your relationship. A few states are also hostile to certain cohabitation contracts or treat oral agreements between partners very differently from written ones, which is one more reason to put everything in writing and check your state's approach.

Why "it depends on your state" is the real answer

Family law is overwhelmingly state law, and this topic is a clear example. There is no controlling federal statute that tells you whether your relationship is a marriage or how your agreement will be judged. States differ on:

• Whether new common-law marriages can form at all — only a handful of states allow it, and several others recognize one validly created elsewhere.
• The exact test for a common-law marriage and how courts weigh evidence like joint taxes, shared accounts, or calling each other spouses.
• Whether domestic partnerships exist and what rights they carry.
• How agreements are enforced — disclosure rules, the unconscionability standard, and whether independent attorneys are required.

Because of this, the safest move is to confirm the rules for your state. Our per-state pages in this cluster walk through each state's position on common-law marriage, domestic partnerships, and the agreements that fit.

What you can do

1. Pin down your actual legal status. Are you common-law married under your state's specific test, registered in a domestic partnership, or just living together? The answer dictates which document you need.
2. Pick the matching tool. A genuine marriage (including common-law) points to a prenup or postnup; a partnership or cohabitation points to a partnership or cohabitation agreement.
3. Put it in writing and sign it. Oral promises between partners are hard to prove and, in some states, unenforceable. Written, signed agreements are the norm courts expect.
4. Exchange honest financial disclosure. List your assets and debts for each other, or sign a clear written waiver if you choose to skip it. Hidden finances are a leading reason agreements get challenged.
5. Sign well before any deadline or wedding, voluntarily. Agreements signed under time pressure or perceived coercion are more vulnerable. Give each person time to read and consider it.
6. Consider separate review. Having each partner consult their own lawyer strengthens an agreement and is required for full enforceability in some states.
7. Check your state's specifics. Confirm whether your state recognizes common-law marriage, what your partnership status grants, and the local enforcement standards before you rely on any document.

Time-sensitive points to watch

• A prenup must generally be signed before the marriage exists. With common-law marriage forming gradually, waiting too long can convert your "prenup" into a postnup with different standards. Sort this out early.
• Moving can change everything. If you relocate, a status that existed (or did not exist) in your old state may be treated differently in the new one. Re-check after a move.
• Registration and termination have their own steps. Some domestic partnerships require a formal dissolution to end, similar to divorce. Do not assume simply moving out ends your legal obligations.

This article is general information, not legal advice; consult a licensed attorney in your state about your specific situation.