To write a relationship contract, two unmarried partners put in writing how they will share money, property, and household responsibilities, and what will happen if they split up, then sign a document that meets the basic requirements of any enforceable agreement. The details are what separate a contract a court will enforce from a piece of paper that falls apart under challenge.
Married couples inherit a default set of rules from their state covering property division, support, and inheritance. Unmarried partners get almost none of that. Without a written agreement, a partner who put years of labor or money into a shared household can walk away with nothing, because most states don’t recognize common-law property rights for cohabitants. A written contract fills that gap. Courts generally enforce these agreements when they satisfy the ordinary requirements of a contract: mutual consent, legal capacity, valid consideration, and lawful subject matter.
What to Put in the Agreement
Financial Responsibilities
Money causes more conflict between cohabitating partners than anything else, so this section deserves the most detail. Spell out the exact percentage or dollar amount each person pays toward rent or mortgage, utilities, groceries, and any other recurring expenses. If you split based on income rather than 50-50, state the formula. A couple with unequal salaries might agree to a 60-40 split on a $2,400 monthly rent, with each person’s share recalculated annually based on current income.
If you plan to open a joint account for shared expenses, document how much each person contributes monthly and what the account can be used for. Keep individual accounts separate for personal spending and specify in the contract that those remain individual property. Address how you handle large joint purchases such as furniture or a vehicle, including who holds the title and how equity gets divided if you separate.
Household Responsibilities
Document who handles cooking, cleaning, laundry, yard work, and pet care, and how often each task gets done. Some couples trade off weekly; others assign tasks permanently based on preference. Either approach works as long as it’s written down.
If one partner takes on significantly more domestic work, you can account for that by adjusting financial contributions. One person doing most of the cooking and cleaning in exchange for a smaller share of rent is a common arrangement. Writing the tradeoff out explicitly prevents the resentment that otherwise simmers for months.
Dispute Resolution
Build in a process for handling disagreements before they escalate. A common approach requires both partners to attend a set number of mediation sessions before either person can take a drastic step like moving out or terminating the agreement. Naming a specific mediation service, or committing to find a neutral third party within a set timeframe, keeps the clause usable rather than aspirational.
Exit Terms
This is where the contract earns its value. Address what happens to a shared lease, jointly purchased property, and overlapping financial accounts if you separate. If you bought a car together, who keeps it and how is the other person compensated? If one partner moved across the country for the relationship, does the agreement include a transition period or financial cushion? Working through these questions while both partners are still cooperating produces far more reasonable terms than negotiating after things fall apart.
What to Leave Out
Certain clauses will get thrown out no matter how carefully you draft them, and including them can cast doubt on the rest of the agreement.
- Child custody and child support. Courts decide these based on the child’s best interests at the time of the dispute, not based on what two adults agreed to in advance. A parent cannot bargain away a child’s right to support. Leave children out of the agreement entirely.
- Anything that reads as payment for a sexual or romantic relationship. If the contract looks like one partner’s obligations are given in exchange for intimacy, courts will refuse to enforce it. Ground the agreement in financial and domestic exchanges, not companionship.
- Illegal or wildly one-sided terms. Any clause requiring illegal activity is void. Terms so lopsided that one partner forfeits all shared property over a minor breach risk being struck down as unconscionable.
Legal Requirements the Contract Has to Meet
None of these requirements are unique to domestic agreements, but missing any one of them gives the other side an easy argument for throwing out the whole document.
Mutual Consent
Both partners must genuinely agree to the same terms. If one person signs under pressure, threats, or deception about what the document contains, the contract is voidable. Rushing the signing or presenting a finished document as a take-it-or-leave-it ultimatum is a bad idea even if both people ultimately sign.
Legal Capacity
Each person must be at least 18 in most states and mentally competent at the time of signing. Someone intoxicated, impaired by medication, or in a mental health crisis lacks the capacity to enter a binding agreement, and a contract signed under those conditions is voidable at the request of the impaired party.
Consideration
Both partners must exchange something of value. In a relationship contract, that usually takes the form of mutual promises: one person agrees to pay a share of rent, the other agrees to cover utilities and handle certain household tasks. The exchange doesn’t need to be equal in dollar terms, but each side must make a genuine bargained-for commitment. A document where only one person makes promises isn’t a contract; it’s a gift.
A Written Document
Always put the agreement in writing. Most states require written contracts for anything involving real property or any agreement that can’t be performed within a year, which covers nearly every cohabitation arrangement. A written document also eliminates the “I never agreed to that” problem that makes verbal agreements worthless in practice.
What Makes It Harder to Challenge
Full Financial Disclosure
Before signing, both partners should exchange a complete picture of their finances: income, savings, debts, and significant assets. If a court later finds that one person hid a major asset or lied about debt, that’s grounds for setting the agreement aside. Attach a simple financial summary as an exhibit so there’s a record of what each person knew at the time.
Independent Legal Review
Each partner should consult their own attorney, separately, before signing. This eliminates the argument that one person didn’t understand the terms or was taken advantage of. Attorney review for a domestic agreement typically runs $250 to $350 per hour, and most reviews take only a few hours. That cost is cheap insurance against a challenge that could unravel the entire document years later.
Severability Clause
A severability clause states that if any single provision is found invalid, the rest of the contract remains intact. Without one, a court that strikes down one problematic clause could void the whole agreement. This matters especially in relationship contracts, where partners sometimes include terms that push legal boundaries without realizing it.
Integration Clause
An integration clause (sometimes called a merger clause) declares that the written document is the complete and final agreement between both parties. Once it’s in place, neither person can later claim there were verbal side deals or outside promises, because evidence of additional terms is generally inadmissible in a dispute.
Review and Amendment Provisions
Relationships change. An agreement written when both partners earn similar salaries can become unfair if one person’s income doubles or one stops working to care for a family member. Include a clause requiring both parties to review the contract at a set interval, such as every two years, and a process for making amendments in writing with both signatures. Some couples add a sunset clause that automatically terminates the agreement after a set period unless both partners affirmatively renew it.
Drafting the Document
Open with the full legal names of both partners and the date the agreement takes effect. If you’re defining terms that appear throughout the document, such as what counts as “shared property” versus individual property, put those definitions near the top.
Use clear headings for each major topic: finances, household tasks, dispute resolution, exit terms, amendments. Each paragraph should cover one topic. Replace vague language like “fair share” or “reasonable amount” with specific numbers, percentages, or frequencies. “Partner A pays 60% of monthly rent” is enforceable. “Partner A pays their fair share” is an invitation to argue.
Write in plain, direct language. Legal jargon doesn’t make a contract more binding. A clause that says “If we break up, we’ll split the joint checking account balance equally as of the separation date” works as well as a dressed-up version, and both partners will actually understand what they signed.
Signing and Storing the Contract
A contract does not have to be notarized to be valid. A signed contract is legally binding without a notary’s stamp. That said, notarization proves both people appeared in person, showed identification, and signed voluntarily. Notary fees range from $2 to $25 per signature depending on your state, so the cost is negligible compared to the protection.
Having one or two witnesses present is another low-cost precaution. Witnesses can later testify that both parties signed willingly and appeared to understand the terms. Most jurisdictions don’t require witnesses for a private contract, but having them costs nothing and eliminates a potential line of attack.
Each partner should keep an original signed copy somewhere secure and protected from damage, such as a fireproof safe, a bank safety deposit box, or an encrypted digital storage service. Don’t keep the only copy in a shared location where one partner could access and destroy it after a falling-out.
Tax Exposure Unmarried Partners Should Plan For
Married couples enjoy an unlimited gift tax exemption between spouses. Unmarried partners don’t. For 2026, the annual gift tax exclusion is $19,000 per recipient.1Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill If one partner transfers more than $19,000 in cash or property to the other in a single year, the excess counts toward the lifetime gift tax exemption and requires filing a gift tax return. If your agreement involves significant asset transfers, such as one partner paying a disproportionate share of a home down payment, address the tax implications in the contract and consider talking to a tax professional before signing.
If You Later Get Married
A cohabitation agreement does not automatically become a prenuptial agreement when you marry. State marital property laws kick in at the wedding and may override terms in your existing contract. Some couples formally convert their cohabitation agreement into a prenup before the marriage, which requires meeting the separate legal requirements for prenups in your state. If you don’t take that step, assume the relationship contract may lose enforceability on issues that marital law now governs, such as property division and spousal support.