Can My Boyfriend or Girlfriend Claim Half My House If We're Not Married?

The short answer

No. If the house is in your name and you are not married, your boyfriend or girlfriend does not get half of it just because you live together, date, or got engaged. The deed controls ownership, not the length or seriousness of the relationship. Whoever is named on the title owns the property. Paying for some groceries, splitting the electric bill, or even chipping in on a few mortgage payments does not automatically buy your partner a share.

That is the default rule in every state. The rest of this page covers the exceptions, because they are real, they are where the money fights happen, and most of the big legal sites barely mention them. A few of these exceptions can hand your partner a genuine claim, so read past the headline before you assume you are safe.

Why "half the house" is mostly a myth

The idea that a live-in partner is entitled to half comes from divorce. When married people split, the court divides their property using one of two systems: community property (roughly a 50/50 split of what was acquired during the marriage, used in California, Texas, Arizona, and a handful of other states) or equitable distribution (a "fair" split, used in most other states). Both systems exist to unwind a marriage.

Unmarried couples get none of that. There is no marital estate to divide, no spousal support, and no presumption that the house gets split. You are treated as two separate individuals who happen to share an address. So the off-title partner does not start with a right to half. They start with nothing, and they have to build a legal claim from scratch using one of the paths below.

5 ways a partner CAN get a claim despite not being married

Here is where the real risk lives. An unmarried partner can end up with a stake in your house through any of these five routes. The first is by far the most common, and the most overlooked.

1. Both names are on the deed. This is the big one. If you put your partner on the title, they are a legal co-owner, full stop. How you hold title then sets the default split: joint tenancy presumes equal shares (and adds a right of survivorship, so if one of you dies the other takes the whole house automatically), while tenancy in common can be unequal shares written right into the deed (say 70/30). The deed language matters more than who paid.
2. A written cohabitation or property agreement. You can both sign a contract that says who owns what, who pays the mortgage, and what happens to the house if you break up. Courts enforce these. This cuts both ways: it can protect you, or it can lock in a share for your partner.
3. An implied or oral "Marvin" agreement. In California and many (not all) states, a partner can argue you had an unwritten understanding to share property or earnings. This comes from Marvin v. Marvin (more below). Some states reject these claims entirely, so it is very state-specific and hard to prove.
4. An equitable claim by a partner who paid in, even if they are off-title. If your partner is not on the deed but poured money or labor into the house, they can ask a court for a constructive trust, resulting trust, unjust enrichment, or quantum meruit. These are the doctrines the big overview pages never name. They are the off-title partner's only real path, and they are genuinely hard to win because the partner has to prove more than "I helped."
5. A common-law marriage. In a small number of states, a couple who agree to be married, live together, and hold themselves out publicly as married can actually be married without a license. If so, every marital right (including the 50/50 divorce split) applies. See the state list below.

The Marvin case, told correctly (because most pages get it wrong)

You will see "palimony" thrown around as if an ex-partner is owed support like an ex-spouse. The case behind that word is Marvin v. Marvin, 18 Cal.3d 660 (1976). The California Supreme Court held that unmarried partners can enforce an express contract about property and earnings, and that even without a written contract a court may find an implied agreement or apply equitable remedies like a constructive trust or quantum meruit. The one limit: a contract cannot be based explicitly on sexual services.

Now the part the lighter pages leave out. On remand, the trial court gave Michelle Triola Marvin $104,000 for "rehabilitation." On appeal, in Marvin v. Marvin, 122 Cal.App.3d 871 (1981), that award was reversed and deleted, because the court found no basis for it in law or equity. She ultimately recovered nothing. So the real lesson of Marvin is the opposite of the myth: an implied-contract claim is a hard, fact-specific uphill fight, not a guaranteed half. And because Marvin is California law, do not assume a "Marvin claim" works the same in your state. Some states, like Illinois, refuse to recognize these cohabitation contracts at all.

Which states still recognize common-law marriage in 2026

If you have a valid common-law marriage, you are married, and the full marital-property rules apply, including the divorce split. But the bar is higher than people think. It is not "we lived together seven years." Using Texas as the clearest example, Texas Family Code Sec. 2.401 requires all three of these: (1) you agreed to be married, (2) you lived together as spouses, and (3) you represented to others that you were married. Living together is never enough on its own. Texas even adds a rebuttable presumption that you were not married if no one files a claim within two years of separating.

A handful of states recognize some form of common-law marriage in 2026. Treat this list as a starting point and confirm current status for your state, because legislatures keep changing it. (Rhode Island, for example, still recognizes it as of 2026; a 2025 bill to abolish it, H5258, stalled in committee, and lawmakers may revisit it.) Also important: every state must recognize a common-law marriage that was validly formed in a state that allows it, so this can follow you when you move.

How a breakup actually splits a co-owned house (it's not automatic 50/50)

Say both names are on the deed and you split up. People assume the house just gets cut in half. It does not work that way. If you cannot agree on who keeps it or how to sell, the legal exit is a partition action: one co-owner sues to force a sale (or, rarely, a physical division), and the court divides the proceeds.

And the division is not blind. Even where the deed says joint tenancy and 50/50, a partition court runs an accounting with credits and offsets. A co-owner who paid more of the down payment, more of the mortgage, more of the property taxes, or who paid for real improvements can be credited for those amounts before the remainder is split. So the title presumption sets the starting point, and the accounting adjusts the cash-out. This partition-with-credits mechanism is one of the most useful things to understand and one of the most consistently skipped by the big overview pages.

The tax traps almost no one mentions

Two federal-tax issues hit unmarried couples and homes, and the legal-overview pages skip both.

There is a second, quieter cost to deeding a partner in. A gift carries your original cost basis over to them (carryover basis), while property someone inherits through a will or survivorship can get a stepped-up basis to its value at death. In plain terms, gifting now can set your partner up for a bigger capital-gains tax later than if they had inherited the same share. It is worth pricing out with an accountant.

On the income-tax side, a common question is who deducts the mortgage interest. Under IRS Publication 936, you can deduct home mortgage interest only if you are legally liable for the loan and you actually paid the interest. So a partner who is not on the mortgage generally cannot deduct it, even if they sent money toward the payment. If you co-own and are both on the loan, you each deduct the share you actually paid. Do not both claim the same interest.

Decision tool and protect-yourself checklist

Run your situation through this quick logic to see roughly where you stand. It is a sanity check, not a substitute for a lawyer.