A cohabitation agreement in New York is a written contract between unmarried partners who live together, setting out how they will handle property, money, and shared obligations during the relationship and if they split up. Because New York does not recognize common law marriage and gives unmarried couples no automatic property or support rights, this contract is the main way partners can protect themselves financially.
Why the Agreement Matters in New York
Living together for years, even decades, creates no legal rights between unmarried partners in New York. Common law marriage was abolished in 1933, and nothing has replaced it. If the relationship ends without a written agreement, assets follow legal title. If your name isn’t on the deed or the account, you likely walk away with nothing, no matter how much you contributed.
The controlling case is Morone v. Morone, decided by the New York Court of Appeals in 1980. The court held that an express, written contract between unmarried partners is enforceable, but refused to recognize implied agreements based on the relationship itself.1H2O Open Casebook. Morone v. Morone A court will not look at how you and your partner behaved and infer a deal from it. A verbal promise of “half of everything” is essentially worthless in a New York courtroom.
Morone also treated everyday contributions like housekeeping and cooking as voluntary unless a written agreement says otherwise. One limit built into the case law: the agreement cannot rest on the sexual aspect of the relationship as consideration. Express contracts between unmarried partners are enforceable “provided only that illicit sexual relations were not part of the consideration of the contract.”1H2O Open Casebook. Morone v. Morone For agreements grounded in financial and property terms, this isn’t a real obstacle.
Without a written agreement, your only fallback is a constructive trust claim. That requires proving a confidential or fiduciary relationship, a specific promise, a transfer of money or property made in reliance on that promise, and unjust enrichment. Most people can’t clear all four. As the court put it in M v F, “Unless and until the law imposes equitable distribution on unmarried couples, in New York, at least, the legal status of marriage remains vitally important to establishing the economic rights of members of a couple.”2New York Courts. M v F, 2010 NY Slip Op 50563(U)
What You Can Put in a Cohabitation Agreement
Property Ownership and Division
The agreement can define what each partner treats as separate property, which usually includes assets acquired before moving in together, inheritances, and personal gifts. It can also set out how jointly acquired property will be divided, including ownership percentages that differ from whatever appears on a title or deed. If you paid 70% of the down payment on a home titled only in your partner’s name, the agreement can reflect that.
A caveat worth stressing: a cohabitation agreement alone does not transfer real estate. If the agreement says you own half a property, you still need a deed that reflects that ownership. The agreement creates a contractual right between the two of you; it does not override what’s recorded at the county clerk’s office.
Household Expenses and Debt
Partners can lay out how they’ll split rent, utilities, groceries, and other shared costs, either evenly or in proportion to income. The agreement should also address debts each partner brings in. Without a written arrangement, you’re generally not liable for your partner’s individual debts. Open a joint credit card or co-sign a loan, though, and both of you are on the hook for the full balance. A creditor can pursue either one of you for the entire amount, even after a breakup.
Financial Support After Separation
New York does not award alimony or maintenance to unmarried partners. A cohabitation agreement can fill that gap by creating a contractual obligation for one partner to provide temporary support if the relationship ends. Courts enforce these provisions as ordinary contract terms, so be specific about amount, duration, and any conditions that trigger or end the payments.
Inheritance Intentions
This is where many unmarried couples get blindsided. Under New York’s intestacy statute, if your partner dies without a will, the estate goes to a surviving spouse, children, parents, siblings, or more distant blood relatives. An unmarried partner inherits nothing, no matter how long you lived together.3New York State Senate. New York Estates Powers and Trusts Law 4-1.1 – Descent and Distribution of a Decedent’s Estate
A cohabitation agreement can state each partner’s intentions, but it does not substitute for a will. You need a properly executed will, and possibly a revocable trust, that lines up with what the cohabitation agreement promises. If the agreement says your partner gets the house but the will leaves everything to a sibling, the will controls.
What the Agreement Cannot Do
Child Custody, Visitation, and Support
These subjects are off-limits. New York Family Court has exclusive jurisdiction and must base custody, visitation, and support decisions on the child’s best interests at the time the issue comes before the court, not on what the parents agreed to years earlier in a private contract.4New York State Senate. New York Family Court Act 661 – Jurisdiction
Unconscionable or Illegal Terms
A provision so one-sided that a court finds it fundamentally unfair, such as one partner forfeiting everything on separation while the other keeps all assets, will likely be struck down. Clauses requiring illegal conduct are unenforceable. Courts can refuse to enforce an unconscionable clause while leaving the rest of the agreement intact.
Medical Decisions and Financial Authority
A cohabitation agreement does not give your partner the right to make medical decisions for you. If you’re incapacitated and haven’t designated your partner in a separate document, the hospital will look to your legal next of kin, and an unmarried partner has no standing in that hierarchy.
New York’s Health Care Proxy Law allows any competent adult to appoint a health care agent, but you must do so in a separate health care proxy form.5New York State Senate. New York Public Health Law 2981 – Health Care Proxy Access to medical records requires a separate written authorization under federal privacy rules.6Department of Health and Human Services. HIPAA and Marriage Consider a durable power of attorney for finances too, so your partner can handle bills and banking if you can’t. Three documents together, the health care proxy, the financial power of attorney, and the cohabitation agreement, cover the ground married couples get automatically.
Federal Benefits
No matter how thorough your agreement is, it cannot unlock benefits reserved for married couples. Unmarried partners cannot file a joint federal income tax return. The IRS sets filing status based on marital status on the last day of the tax year, and unmarried individuals file as single or, with a qualifying child, as head of household.7Internal Revenue Service. Filing Status A partner who provides more than half of the other’s support and meets other criteria may sometimes claim the partner as a qualifying relative dependent, subject to a low gross income cap.8Internal Revenue Service. Dependents
Social Security survivor benefits are unavailable to unmarried partners. The federal Family and Medical Leave Act excludes unmarried partners from its definition of “spouse,” so you have no federally protected right to unpaid leave to care for a seriously ill partner.9U.S. Department of Labor. Fact Sheet 28L – Leave Under the FMLA for Spouses Some New York employers offer domestic partner benefits voluntarily, but nothing in the law guarantees them.
What Makes the Agreement Valid
Written and Signed
An oral cohabitation agreement is not enforceable. Morone requires an express, written agreement.1H2O Open Casebook. Morone v. Morone New York’s Statute of Frauds reinforces this, voiding certain agreements, including those not to be performed within one year, unless they are in writing and signed by the party to be held.10New York State Senate. New York General Obligations Law 5-701 – Agreements Required to Be in Writing Most cohabitation arrangements are open-ended, so the writing requirement is effectively mandatory.
Notarized Acknowledgment
Having both signatures acknowledged before a notary is standard practice and strongly recommended. New York requires this formality for prenuptial agreements under the Domestic Relations Law, which requires such agreements to be “in writing, subscribed by the parties, and acknowledged or proven in the manner required to entitle a deed to be recorded.”11New York State Senate. New York Domestic Relations Law 236 – Matrimonial Actions Cohabitation agreements fall under general contract law rather than that statute, but following the same standard adds a strong presumption of authenticity.
Full Financial Disclosure
Both partners must give honest, complete information about income, assets, debts, and significant obligations before signing. A court can set aside the whole agreement if one partner later proves disclosure was incomplete or false. Attaching financial statements or net worth summaries as exhibits creates a record that disclosure actually happened.
Voluntary Consent
Duress, coercion, or fraud can void the contract. Timing matters. Presenting the agreement for signature on the day the moving truck arrives looks coercive. Give your partner time to read it, ask questions, and consult a lawyer.
Independent Legal Counsel
Separate attorneys aren’t strictly required, but hiring your own is one of the strongest protections against a later challenge. If both partners had independent counsel, it becomes very hard for either one to claim later that they didn’t understand what they signed. A single attorney cannot represent both sides. Two attorneys up front cost far less than litigating a broken agreement.
Updating the Agreement or Converting to a Prenup
Partners can amend the agreement at any time, but any changes should be in writing and signed by both. Verbal amendments create exactly the ambiguity the original agreement was meant to prevent. Revisit the document when circumstances shift, such as a large inheritance or buying property together.
If you decide to marry, the cohabitation agreement does not automatically convert into a prenuptial agreement. The Domestic Relations Law imposes specific requirements for prenups, including the acknowledgment formality and fairness standards at the time of divorce.11New York State Senate. New York Domestic Relations Law 236 – Matrimonial Actions A cohabitation agreement that met general contract standards might not clear that bar. Draft a new prenup before the wedding that carries forward whatever terms you want to keep.