Living with a partner without marrying affects your rights and finances in ways most people underestimate: you have no automatic claim to shared property, no spousal tax benefits, no inheritance if your partner dies without a will, no Social Security survivor benefits, and no default authority to make medical decisions for each other. Marriage bundles dozens of legal protections together automatically. Cohabitation gives you almost none of them, and the gaps have to be closed deliberately, in writing, before you need them.
What follows is where those gaps actually show up, and what you can do about each one.
When Living Together Counts as Cohabitation
Not every shared address qualifies as cohabitation in the legal sense. Courts look at a cluster of factors together: how long you have lived together, whether you split rent and groceries, whether your finances are intertwined through joint accounts or shared credit cards, and whether friends, family, and neighbors treat you as a committed couple. No single factor is decisive, and roommate arrangements do not become cohabitation just because they last a long time.
The legal framework for recognizing any rights at all between unmarried partners traces to the California Supreme Court’s 1976 decision in Marvin v. Marvin, which held that courts should enforce express contracts between unmarried partners and should look to the couple’s conduct for evidence of an implied understanding about property. The one thing courts will not enforce is an agreement whose sole basis is sexual services.1Justia. Marvin v. Marvin Marvin‘s influence spread, but unevenly: some states enforce oral and written agreements, others require everything in writing, and a few refuse to recognize implied arrangements based on living together alone.
Cohabitation Is Not Common Law Marriage
Living together for years does not make you married. Common law marriage is a real legal status, but only about ten states and the District of Columbia recognize it, and the requirements typically include mutual intent to be married, cohabiting as spouses, and publicly presenting yourselves as married. There is no magic number of years. The widespread belief that seven years of cohabitation creates a common law marriage is a myth.2National Conference of State Legislatures. Common Law Marriage by State
If you qualify in a state that recognizes it, you get the full rights of a married spouse, including property division at divorce, inheritance, and government benefits. The Social Security Administration defers to state law and uses a “holding out” test — whether the couple lived together and presented themselves to others as married.3Social Security Administration. GN 00305.075 State Laws on Validity of Common-Law Non-Ceremonial Marriages If your state does not recognize common law marriage, the length of your relationship is legally irrelevant to your marital status.
Property Rights During and After the Relationship
When a marriage ends, state law divides assets through equitable distribution or community property rules. When a cohabiting relationship ends, neither framework applies. Ownership comes down to whose name is on the deed, the title, or the account.
If only one partner holds title to the home, the other has no legal claim to the equity, even after years of paying toward the mortgage, funding renovations, or maintaining the property. A non-titled partner trying to recover contributions faces an uphill fight. Some courts allow claims based on oral or written agreements; others require a written contract. A few jurisdictions will apply equitable doctrines like constructive trust or unjust enrichment, but only with specific proof that one partner was unfairly enriched at the other’s expense.
The practical rule is blunt: if your name is not on it, assume you do not own it unless a written agreement says otherwise.
Tax Treatment for Unmarried Partners
The IRS does not recognize cohabitation. Filing status is based on marital status on the last day of the tax year, so unmarried partners each file as single, or as head of household if they have a qualifying child. Joint returns are reserved for married couples.4Internal Revenue Service. Filing Status You cannot combine incomes and deductions, and the combined tax bill is sometimes higher than a married couple with the same total income would pay.
Partner Health Insurance Creates Imputed Income
Some employers extend health coverage to domestic partners, but federal law does not require it, and the tax treatment differs sharply from spousal coverage. If your partner is not your tax dependent, the fair market value of the employer-paid portion of their premium is taxable income to you. It shows up on your W-2 and is subject to income tax and payroll tax withholding. For a spouse, the same employer contribution is tax-free. Depending on the plan, imputed income for a partner’s coverage can add several thousand dollars to your taxable wages each year.
Gifts Between Partners
Married couples can transfer unlimited assets to each other during life or at death without triggering gift or estate tax, through the unlimited marital deduction.5Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse Unmarried partners get no such benefit. Transfers above the annual gift tax exclusion of $19,000 per recipient in 2026 count against the giver’s $15,000,000 lifetime exclusion.6Internal Revenue Service. What’s New – Estate and Gift Tax Most people never hit the lifetime cap, but larger moves — adding a partner to a deed, leaving a substantial estate — need more deliberate planning than the same transfers between spouses.
Alimony From a Prior Marriage
If you receive spousal support and begin cohabiting with a new partner, your ex-spouse may have grounds to reduce or terminate payments. A majority of states allow courts to modify alimony when the recipient enters a marriage-like living arrangement, on the theory that sharing household expenses reduces the financial need that justified the original order.
Standards vary. Some states require proof that the new relationship actually changed the recipient’s finances. Others treat cohabitation as an automatic trigger for termination regardless of financial impact. A few require the cohabitation to be continuous and open, or to last a minimum period such as three months. The paying spouse usually has to file a motion with evidence — shared leases, utility records, witness testimony. Many divorce decrees include a cohabitation clause spelling out the consequences, so check the language of your own decree before you make any decisions about moving in with someone new.
What Happens When One Partner Dies
This is the most dangerous gap, because death is irreversible and so are its legal consequences.
If your partner dies without a will, you inherit nothing. Intestate succession laws in every state direct the estate to legal spouses, children, parents, and siblings. An unmarried partner is treated as a stranger to the estate, regardless of how long you were together or how entangled your finances were. A will, a trust, or beneficiary designations on accounts are the only way to override that default.
Estate Tax With No Marital Deduction
When a married person dies, their entire estate can pass to the surviving spouse free of federal estate tax. Unmarried partners do not qualify. Assets above the $15,000,000 lifetime exclusion that pass to a surviving unmarried partner are taxed at a top rate of 40%.6Internal Revenue Service. What’s New – Estate and Gift Tax Married couples can also transfer unused exclusion through portability. Unmarried partners cannot. At higher net worths, this makes estate planning essentially mandatory.
No Social Security Survivor Benefits
An unmarried partner cannot collect Social Security survivor benefits on a deceased partner’s earnings record. Only a surviving spouse qualifies, or in some cases a divorced spouse from a marriage that lasted at least ten years.7Social Security Administration. Survivors Benefits For long-term couples who never married, that can mean tens of thousands of dollars a year in lost income when one partner dies. There is no workaround. You either meet the legal definition of spouse or you do not qualify.
Medical Decisions and Hospital Access
Married spouses are typically the default decision-makers when their partner is incapacitated. Unmarried partners are not. If your partner is unconscious and you have no legal documents, the hospital will turn to blood relatives.
Federal regulation does protect visitation. Every hospital participating in Medicare or Medicaid must allow patients to designate their own visitors, including a domestic partner, and cannot restrict visitation based on the visitor’s relationship, sexual orientation, or gender identity.8eCFR. 42 CFR 482.13 – Patient’s Rights But visitation is not decision-making. Being allowed in the room does not let you authorize surgery or direct treatment.
Two documents close the gap. A durable power of attorney for healthcare (sometimes called a healthcare proxy) gives your partner authority to make medical decisions if you cannot. A living will, or advance directive, records your specific wishes on things like life support. Both are governed by state law, so execution requirements vary, but both are inexpensive to put in place and extremely costly to be without.
Children and Parental Rights
The biological mother’s parental rights attach at birth. The father’s rights do not. Federal law requires every state to maintain programs for establishing paternity, including in-hospital voluntary acknowledgment, where an unmarried father can sign a legal document when the child is born.9eCFR. 45 CFR 303.5 – Establishment of Paternity If paternity is not acknowledged voluntarily, the state child support agency or the mother can seek a court order, which may involve genetic testing.
A non-biological partner raising a partner’s child has a harder path. Without a biological tie, legal parenthood generally requires adoption. Stepparent adoption usually requires marriage to the biological parent and termination of the other biological parent’s rights. For unmarried partners, second-parent adoption is available in some states and lets a partner adopt without the biological parent giving up their rights. Availability and requirements vary. Without legal recognition, a non-biological partner who has raised a child for years can lose all custody and visitation if the relationship ends.
Housing After a Breakup
When a cohabiting couple splits, the partner named on the lease or deed holds the legal cards, but not as completely as people often assume. If both names are on the lease, both have equal rights to stay through the term. If only one name is on it, the other has far less protection, but still cannot simply be thrown out.
Living together and sharing expenses can create an oral tenancy under landlord-tenant law. The partner who controls the home has to follow formal eviction procedures to remove the other. Changing the locks, cutting off utilities, or forcing a partner out without a court order is illegal in most jurisdictions regardless of whose name is on the lease. Eviction requires written notice (typically 30 days for a month-to-month arrangement) and, if the partner does not leave, a court hearing. This is where people routinely make expensive mistakes after an ugly breakup.
A Cohabitation Agreement Closes Most of the Gaps
A cohabitation agreement is a written contract between unmarried partners covering how property, finances, and responsibilities are handled during the relationship and if it ends. Courts have recognized these as enforceable since Marvin, provided they meet standard contract requirements.1Justia. Marvin v. Marvin
What to Put in It
List each partner’s individual assets — real estate, retirement accounts, vehicles, significant personal property. Disclose existing debts, including student loans and credit card balances. Then address the going-forward questions:
- How housing costs, insurance, and utilities will be split (equally, proportionally by income, or by category).
- What happens to each person’s share of any property you buy together if you separate.
- Whose debts are whose. Each partner’s existing debts should stay their own unless you agree otherwise in writing. The doctrine of necessaries that lets creditors pursue a spouse for the other’s debts generally does not reach unmarried partners, so creditors cannot come after you unless you co-signed or jointly incurred the debt.
- How shared property gets divided on separation, who stays in the home, and what notice period applies.
Use current numbers from recent statements or returns. Vague estimates weaken the agreement and invite challenges.
Signing It Properly
The agreement must be written, signed voluntarily by both partners, and free of illegal provisions. An agreement based primarily on sexual services will not be enforced. Sign in front of a notary; some jurisdictions also require one or two independent witnesses. Keep original signed copies in a secure location. These documents are generally not filed with a court at signing, but proper execution is what lets you produce and enforce the document later. A few hundred dollars on legal review upfront is a fraction of what a contested dispute costs when there is no agreement at all.