No, you don’t have to be formally married to be considered a spouse, but the alternatives are narrow. A valid common-law marriage, recognized in about a dozen jurisdictions, makes you a legal spouse with the same rights as any other married person. Domestic partnerships and civil unions are a different animal: they give you some of what marriage gives, but not spousal status under federal law. Outside those paths, long-term cohabitation alone will not make anyone your spouse, no matter how many years have passed.
The distinction matters because spousal status controls taxes, inheritance, Social Security, retirement accounts, hospital decisions, and immigration. Getting it wrong at the wrong moment can shut a partner out entirely.
What the Law Requires for Spousal Status
A formal marriage is the clearest path. You get a marriage license from a local government office, have a ceremony conducted by an authorized officiant with witnesses, and the marriage is recorded. Every state and the federal government will honor it. License fees generally run between $20 and $100.
Not every ceremony produces a valid marriage. A marriage is void from the start if it involves close blood relatives or if one partner was already married to someone else. Voidable marriages, by contrast, remain legally binding until a court declares them invalid; grounds include fraud, coercion, mental incapacity at the ceremony, or one spouse being below the legal age of consent.
Same-sex couples have the same right to marry and be recognized as spouses as opposite-sex couples. The Supreme Court held in Obergefell v. Hodges that the Fourteenth Amendment requires every state to license and recognize same-sex marriages,1Justia. Obergefell v. Hodges, 576 U.S. 644 (2015) and United States v. Windsor struck down the part of the Defense of Marriage Act that had defined “spouse” as opposite-sex for federal purposes.2Justia. United States v. Windsor, 570 U.S. 744 (2013) A valid same-sex marriage carries identical federal spousal status.
Common-Law Marriage: The Real Exception
Common-law marriage lets a couple become legally married without a license or ceremony. It exists in only a handful of jurisdictions today, including Colorado, Iowa, Kansas, Montana, Rhode Island, Texas, Utah, and the District of Columbia. A few other states recognize common-law marriages formed before a specific cutoff date but no longer allow new ones.
Requirements vary, but recognizing states generally look for three things: both partners intend to be married, they present themselves publicly as married, and they live together. Living together for a long time is not enough on its own. No state has a rule that says a certain number of years of cohabitation creates a marriage. The couple has to actually hold themselves out as spouses, using conduct like a shared last name, joint tax returns, and introducing each other as husband or wife.
Once a common-law marriage is validly established in a state that recognizes it, other states generally must honor it under the Full Faith and Credit Clause.3Congress.gov. Constitution Annotated – Overview of Full Faith and Credit Clause A common-law spouse has the same legal rights as a formally married one, and ending the relationship takes a formal divorce. You cannot simply move apart and call it done.
Domestic Partnerships and Civil Unions Are Not the Same as Marriage
Domestic partnerships and civil unions are registered legal relationships that carry some but not all of the rights of marriage. They require formal registration with a state or local government; they don’t form automatically through cohabitation. The rights involved vary widely by jurisdiction. Some grant hospital visitation, insurance coverage, and parental recognition close to what marriage provides. Others offer much less.
The biggest gap sits at the federal level. The IRS does not treat registered domestic partners or civil union partners as married. They cannot file federal returns as married filing jointly or married filing separately, and must file as single or, if they qualify, as head of household.4Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions That means no unlimited marital deduction for estate and gift taxes, no spousal IRA contributions, and none of the other federal benefits that flow only to legal spouses. Domestic partnership gives you a legal relationship. It does not give you spousal status.
The Putative Spouse Doctrine
Some states protect a partner who genuinely believed they were entering a valid marriage when they were not. This comes up most often in bigamy cases, where one partner is already married and the other has no idea. Under the putative spouse doctrine, the good-faith partner can still receive marital property rights even though the marriage was technically void. It is an equitable safeguard, not a widespread rule, and it requires proving the good-faith belief was reasonable.
What You Get With Spousal Status That You Don’t Get Without It
The practical stakes of spousal status show up in specific programs and rules. This is why the question matters.
Taxes
Married couples can file joint federal returns, which often produces a lower combined tax bill. Property passing to a surviving spouse is deductible from the taxable estate under the unlimited marital deduction, meaning no federal estate tax on those transfers regardless of amount.5Office of the Law Revision Counsel. 26 U.S. Code 2056 – Bequests, Etc., to Surviving Spouse Married U.S. citizen spouses can also make unlimited lifetime gifts to each other without triggering gift tax.6Internal Revenue Service. Frequently Asked Questions on Gift Taxes for Nonresidents Not Citizens of the United States Where the recipient spouse is not a U.S. citizen, the deduction isn’t unlimited, but gifts up to $194,000 per year in 2026 are excluded. Unmarried partners, including domestic partners, are subject to the ordinary $19,000 annual gift tax exclusion when gifting to each other.7Internal Revenue Service. Gifts and Inheritances
Social Security
Survivor benefits go to a spouse who was married to the deceased worker for at least nine months before death,8Social Security Administration. Who Can Get Survivor Benefits with the nine-month rule waived for accidental deaths or line-of-duty military deaths.9Social Security Administration. 404. Exception to the Nine-Month Duration of Marriage Requirement Divorced spouses can qualify if the marriage lasted at least ten years.10Social Security Administration. More Info – If You Had a Prior Marriage Unmarried partners get nothing, regardless of relationship length.
Retirement Accounts
Under ERISA, pension plans and many 401(k) plans must pay benefits to the surviving spouse unless that spouse has signed a written waiver consenting to a different beneficiary.11GovInfo. 29 U.S. Code 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity In divorce, dividing one of these accounts requires a Qualified Domestic Relations Order.12U.S. Department of Labor. QDROs – An Overview FAQs Unmarried partners have no automatic claim to a former partner’s retirement account, no matter how long they were together.
Medical Decisions
Spouses generally have automatic authority to make healthcare decisions for an incapacitated partner. Unmarried partners typically do not. Closing that gap requires a durable power of attorney for health care, sometimes called a health care proxy, naming your partner as the person authorized to act if you cannot communicate.13National Institute on Aging. Choosing a Health Care Proxy Each state has its own form, and most require notarization or witnesses.
Family and Medical Leave
FMLA allows eligible employees up to 12 weeks of unpaid, job-protected leave per year to care for a spouse with a serious health condition.14U.S. Department of Labor. Family and Medical Leave (FMLA) The regulation defines spouse to include a partner in a same-sex or common-law marriage entered into in a state recognizing such marriages.15eCFR. 29 CFR 825.122 Domestic partners and unmarried cohabitants do not qualify.
Immigration
U.S. citizens and lawful permanent residents can sponsor a spouse for a green card by filing a petition with USCIS along with a civil marriage certificate.16U.S. Citizenship and Immigration Services. Bringing Spouses to Live in the United States as Permanent Residents Same-sex spouses have the same immigration eligibility as opposite-sex spouses.17U.S. Department of State. Nonimmigrant Visa for a Spouse (K-3) No immigration pathway exists based on a domestic partnership or unmarried cohabitation.
If You’re Not a Spouse: What You Can Still Do
Long-term partners without spousal status still have tools. None of them replicate the full package of marital rights, but they can close the most dangerous gaps.
- A healthcare power of attorney names your partner to make medical decisions if you’re incapacitated. Without one, hospitals turn to your closest blood relative.
- A will or living trust is the only way to direct assets to an unmarried partner. If you die without one, intestacy laws send everything to blood relatives, and your partner receives nothing.
- A written cohabitation or property agreement governs how you share expenses, own property, and divide assets if the relationship ends. Proving an unwritten deal in court is difficult and expensive.
- Beneficiary designations on life insurance, IRAs, and payable-on-death bank accounts let you name your partner directly. These override a will, so they need updating whenever your situation changes.
- Joint titling on property or bank accounts as joint tenants with right of survivorship passes the asset to your partner automatically at death, without probate.
The pattern is simple. Married spouses get most of these protections by default. Unmarried partners must affirmatively create each one through separate legal documents. Skipping the healthcare proxy or the will can leave a partner with no legal standing at the moment it matters most.