A cohabitation agreement is a written contract that lets unmarried partners decide in advance who owns what and who owes what. Moving in together blends finances faster than most couples expect. Rent gets split, one partner covers a car payment, both contribute to a down payment, and the paperwork rarely reflects any of it.
If the relationship ends, New York law gives unmarried partners almost nothing to fall back on, because the protections that come with divorce are tied to marriage. At Hartin Divorce & Family Law, we draft agreements that settle those questions while both partners still agree on the answers. If you and your partner are planning to live together, call (516) 666-0539 to talk through what an agreement should cover.
A cohabitation agreement is a contract between two people who live together without marrying. It records what each partner owns going in, how shared costs are handled, and what happens to jointly acquired property if the relationship ends. Some couples call it a living together agreement or a cohabitation property agreement, and those terms mean the same thing.
Courts here treat these agreements as ordinary contracts. The Court of Appeals held in Morone v. Morone that an express agreement between unmarried partners is enforceable, so long as the agreement rests on something other than the personal relationship itself.
That same decision drew a hard line in the other direction. Courts will not imply a contract from the fact that two people lived together and shared their lives, however long the arrangement lasted. The distinction is the reason the document matters: Without an express agreement, there is usually nothing for a court to enforce.
Consider a couple who buy a home together, with one partner supplying the down payment and the other covering the mortgage for six years. If only one name appears on the deed and nothing was written down, the partner who paid the mortgage may have no claim at all.
Domestic Relations Law Section 11 requires a license and a ceremony performed by an authorized officiant before a marriage is valid. There is no informal alternative. A couple who live together for thirty years, share a last name, and introduce each other as spouses are not married under state law. One narrow exception exists. Courts in this state will recognize a common law marriage that was validly formed in another state that still permits them.
Equitable distribution exists only inside a matrimonial action. Domestic Relations Law Section 236 Part B governs how marital property is divided and how maintenance is awarded, and it applies when a court grants a divorce, an annulment, or a dissolution. Unmarried partners never reach that statute.
Inheritance works the same way. Under Estates, Powers and Trusts Law Section 4-1.1, property left without a will passes to a surviving spouse, children, parents, and more distant blood relatives in a fixed order. A long-term partner appears nowhere on that list.
The practical result is that a surviving partner can be left with no claim to a home they helped pay for and no standing in the estate. The same gap opens during a separation. There is no statutory formula to divide what the couple built together, and no obligation for either partner to support the other afterward.
Because the agreement is a contract, it succeeds or fails on contract principles. The first of those principles is writing.
General Obligations Law Section 5-701 voids an agreement that by its terms cannot be performed within one year unless it is written and signed by the party being held to it. A cohabitation arrangement almost always runs longer than a year.
Building an agreement that holds up usually involves the following steps:
Skipping any of these steps leaves a partner room to argue later that the agreement was never truly agreed to.
Courts also look at fairness. An agreement that leaves one partner with nothing after years of shared contribution invites a challenge. Terms tied to the personal relationship rather than to property or money will not be enforced at all.
The scope is broad, because the partners set it themselves. Most agreements address a few core categories:
Partners can also address financial support after a separation, though those terms need careful drafting to stay enforceable.
At Hartin Divorce & Family Law, we work through each category with both partners before anything is drafted, because a term nobody understood is a term somebody will contest. To talk through what belongs in your agreement, call (516) 666-0539 to arrange a free case evaluation.
Partners can write whatever they like about children, and a court remains free to disregard it. Custody and parenting time are decided on the best interests of the child at the time of the dispute, not on terms two people agreed to years earlier.
Child support works the same way. The obligation belongs to the child, so parents cannot contract it away or fix it at a figure the statutory calculation would not support.
Also, a cohabitation agreement governs the relationship between the partners. It does not give a partner authority to make medical decisions, and it does not create an inheritance.
Medical authority comes from a health care proxy, which any competent adult can sign in front of two adult witnesses without a notary. Inheritance requires a will, because the intestacy statute will not supply one.
Most couples we advise sign all three documents together, since each one closes a gap the others leave open.
The best moment is before the finances mix. Once a joint account has been open for three years and both partners have paid into a mortgage, reconstructing who contributed what becomes an argument rather than a record.
Signing a lease together counts as mixing finances. Both names on a lease create joint liability for the full rent, which means one partner can be pursued for the entire balance after the other moves out. An agreement can set out how that exposure is handled.
A few points in a relationship make the conversation especially worthwhile. Buying property together is the clearest one, because title alone rarely reflects what each partner actually put in.
Another is a decision by one partner to step back from paid work to raise children or support the other's career. That partner gives up income without gaining any of the protections a spouse would have.
Agreements also need revisiting. A move, an inheritance, a new business, or a child changes the financial picture enough that terms written years earlier may no longer describe the arrangement the partners actually have.
Practically, yes. Any arrangement lasting more than a year must be written and signed to be enforceable, and a written document is far easier to prove.
No. Courts decide custody on the child's best interests and calculate support under statute, regardless of what the partners agreed between themselves.
We recommend it. Independent counsel for each partner removes the conflict of interest and makes the agreement considerably harder to challenge later.
Yes. Both partners can amend it in a signed writing, and we suggest revisiting the terms after a move, a major purchase, or a job change.
No. A prenuptial agreement takes effect on marriage under the Domestic Relations Law, while a cohabitation agreement governs partners who are not marrying.
Marriage changes the legal framework. Couples who marry should replace the agreement with a prenuptial or postnuptial agreement drafted for that purpose.
The gap that Section 236 leaves for unmarried partners does not close with time. It stays open until two people write down what they have decided between themselves. Sorting that out while you still agree is far easier than sorting it out after you no longer do. Most couples find the conversation clarifying rather than uncomfortable, because it replaces assumptions with terms both people have read.
Our firm focuses exclusively on matrimonial and family law, and Thomas Hartin and Christina Nankervis draft agreements for unmarried couples who want their arrangement settled in writing. Our team will review your circumstances and explain what an enforceable agreement would need to contain.
Call Hartin Divorce & Family Law at (516) 666-0539 or reach us through our contact page to schedule a free case evaluation with a New York cohabitation agreement attorney.
