Financial Planning for Unmarried Couples: What Cohabiting Partners Need to Know

Tens of millions of American couples share a home, finances, and a future without being legally married. The financial and legal gaps are significant — and mostly invisible until something goes wrong. Not legal or tax advice — your specifics matter.

Estate planning: the most urgent gap

In all 50 states, if you die without a will, your assets pass to your legal heirs — typically your parents or siblings, not your partner. This is true even if you've lived together for 20 years, own a home together, and have children. Your partner has no automatic inheritance right under intestate succession law.

The five documents every cohabiting couple needs:

• Will: Explicitly names your partner as heir for any assets that pass through probate. Without it, state law decides — and it won't choose your partner. Each partner needs their own will.
• Beneficiary designations on every account: Retirement accounts (401(k), IRA), life insurance, bank TOD designations, and brokerage POD designations pass outside probate — directly to the named beneficiary. Name your partner explicitly on every account. A will cannot override a beneficiary designation.
• Durable financial power of attorney: If you're incapacitated, your partner has no legal right to manage your finances without this document. Banks will not talk to them; bills won't get paid.
• Healthcare proxy / medical POA: Without it, hospitals may default to your biological family for medical decisions. Your partner has no legal standing to override them.
• HIPAA authorization: Allows your partner to receive medical information. Even a healthcare proxy doesn't automatically grant access to your medical records without a separate HIPAA authorization.

Property titling also matters. If you own a home together, how the deed is titled determines what happens at death. Joint tenancy with right of survivorship (JTWROS) means the surviving partner automatically inherits the decedent's share — no probate required. Tenants in common (TIC) means each owns a separate share that goes through their estate — useful if you want to leave your share to someone other than your partner, but it creates probate complexity. For most cohabiting couples who want the survivor to keep the house, JTWROS is the right structure.

Cohabitation agreement

A cohabitation agreement is essentially a contract between partners that governs property ownership, expense sharing, and what happens if the relationship ends. Unlike a prenuptial agreement — which governs assets at the point of marriage — a cohabitation agreement governs the relationship as it exists now.

Key areas to address:

• Property ownership: Who owns what you brought in? How are jointly purchased items (furniture, car, house down payment) split if you separate?
• Shared expenses: How are rent/mortgage, utilities, and household costs shared? Are these contributions tracked, or treated as gifts?
• Shared real estate: If one partner contributes more to a down payment, how is equity split? What happens if one partner wants to sell and the other doesn't?
• Support if one partner leaves the workforce: If one partner reduces work or stops working to support the household, what financial protections exist if the relationship ends?
• Separation mechanics: Who stays in the home? How are jointly held assets divided? What timeline?

Unmarried couples have no divorce court to adjudicate these disputes. Without an agreement, resolving shared property requires civil litigation — slow, expensive, and relationship-ending in every sense.

Tax planning: filing as single

Unmarried partners cannot file jointly. Each files as Single or, if they have a qualifying dependent, Head of Household. This has several meaningful implications:

• No marriage penalty or bonus: High-earning dual-income couples often face a "marriage penalty" — their combined taxable income pushes them into higher brackets as a joint filer. Unmarried couples avoid this, which can be a meaningful advantage for couples with similar incomes.
• Roth IRA income limits are lower: For 2026, single filers can make a full Roth IRA contribution only if their MAGI is below $153,000; contributions phase out between $153,000 and $168,000.¹ Married couples filing jointly have a higher combined threshold ($236,000–$246,000 for 2026). Each partner's limit is determined independently.
• No spousal IRA: Married couples can fund a spousal IRA for a non-working partner using the working spouse's income. Unmarried partners cannot — each partner must have their own earned income to contribute to an IRA.
• Mortgage interest deduction: Only the person (or persons) whose name is on the loan can deduct mortgage interest. If one partner is listed as the borrower but both pay the mortgage, the non-borrower partner cannot deduct the interest they contributed. Structure co-ownership agreements accordingly.
• Gifts between partners are not tax-free beyond $19,000: The unlimited marital deduction (no gift tax between U.S.-citizen spouses) does not apply to unmarried partners. Gifts above $19,000 per year to your partner require filing Form 709 and reduce your lifetime estate/gift exemption.² This matters if one partner transfers a significant asset (real estate, investment account) to the other.

Retirement planning: each partner is on their own

Married couples can coordinate retirement savings across both spouses' accounts, pool income, and use each other's tax brackets. Unmarried couples have individual limits and no ability to pool.

2026 contribution limits for each individual:

Each partner can max out their own accounts independently. The combined savings capacity of a dual-income unmarried couple is identical to a married couple in dollar terms — but there's no flexibility to allocate across partners. If one partner has access to a strong 401(k) and the other doesn't, you can't rebalance — each is stuck with their own options.

HSA note: You can use your HSA only for your own qualified medical expenses or those of your tax dependents. Your partner's medical costs are not eligible unless they qualify as your tax dependent (they must live with you, earn below $5,200, and you must provide more than half their support). This is a meaningful gap for unmarried couples compared to married ones, where HSA funds can cover either spouse.

Social Security: the biggest long-term gap

Social Security spousal and survivor benefits are available only to legally married couples. For unmarried partners, this creates a significant income gap that often becomes visible only decades later — when it's too late to address.

• No spousal benefit: Married spouses can claim up to 50% of their partner's FRA benefit at their own full retirement age, even with little or no earnings history. Unmarried partners receive only their own earned benefit, regardless of how many years they may have stepped back from the workforce to support the household.
• No survivor benefit: When the higher-earning spouse in a married couple dies, the surviving spouse steps up to the higher benefit. For an unmarried couple, each partner keeps only their own benefit — the partner's SS income stops completely at death. The lower-earning partner's income is not protected.
• The planning implication: An unmarried partner who significantly reduced their career to support the household is exposed to meaningful income risk in old age. Life insurance and a strong personal retirement account are the primary compensating mechanisms.

Health insurance

Options for covering a domestic partner on employer health insurance:

• Employer domestic partner coverage: Many employers extend health benefits to domestic partners. However, unless your partner qualifies as your tax dependent under IRS rules, the fair market value of the employer-provided coverage is imputed income — added to your W-2 and subject to federal income tax and FICA. Married couples have no such imputed income. The cost varies by plan but can add $2,000–$8,000 to annual taxable income depending on the employer's plan value.
• ACA marketplace: Unmarried partners can each purchase their own coverage through the marketplace. Income-based subsidies (premium tax credits) are calculated on each individual's income, filed as Single. You cannot file a joint household application unless you're married.
• COBRA trap: When a marriage ends in divorce, the ex-spouse is entitled to continue health coverage under COBRA for up to 36 months. When an unmarried partnership ends, the partner on the other's plan loses coverage on the date of the breakup — with no COBRA right. Plan accordingly.

Life and disability insurance

For married couples, Social Security survivor benefits and spousal inheritance rights provide a baseline of income protection. For unmarried couples, neither exists. Life insurance is the replacement mechanism.

• Term life insurance: Insurable interest exists for domestic partners — you can purchase a policy on your own life naming your partner as beneficiary, or on your partner's life with their consent. The death benefit passes directly to the named beneficiary, outside probate, with no tax. For a couple where one partner earns significantly more, sizing a 20-year term policy to replace several years of income (or the full mortgage balance) is the core protection.
• Beneficiary designation matters: Name your partner as beneficiary on both your life insurance and retirement accounts. These pass outside a will. Even if your will names your partner, an old beneficiary designation naming a parent or ex will override it.
• Disability insurance: Each partner needs own-occupation disability coverage that covers their individual income. Unlike Social Security disability (which has no spousal benefit) or group LTD (which often caps at 60% of income), private disability coverage can be sized appropriately. Without it, a disability that cuts one partner's income by 60% may threaten shared housing.

If the relationship ends

Married couples have divorce courts — a legal framework that adjudicates asset division, support, and custody. Unmarried couples have civil courts, contracts, and whatever agreements they made in writing.

• Shared real estate requires either a buyout, a sale, or — if neither can be agreed — a partition action filed in court. Partition lawsuits are expensive, slow, and adversarial. A cohabitation agreement with explicit buyout procedures is far better.
• Retirement accounts cannot be divided with a QDRO for unmarried couples. Each partner keeps their own accounts, regardless of what either contributed to support the other during the relationship.
• Joint bank accounts: either partner can withdraw the full balance. Close or separate joint accounts promptly when a relationship ends.
• Beneficiary designations don't auto-update when you break up. Update every account beneficiary as soon as the relationship ends — otherwise your ex gets your IRA.

Sources

1. IRS — 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500. Confirms 2026 contribution limits: 401(k) $24,500, IRA $7,500, Roth IRA single-filer phaseout $153,000–$168,000.
2. IRS — Frequently asked questions on gift taxes. Annual exclusion $19,000 per recipient in 2026; unlimited marital deduction applies only to legally married couples.
3. Social Security Administration — Benefits for spouses. Spousal and survivor Social Security benefits require legal marriage; domestic partners do not qualify.
4. IRS Publication 969 — Health Savings Accounts. HSA funds may only be used for qualified medical expenses of the account holder, spouse, or tax dependents. Unmarried domestic partners are not automatically eligible.

Tax and contribution values verified against IRS 2026 inflation adjustment release (Rev. Proc. 2025-32). Roth IRA phaseout for single filers: $153,000–$168,000 for 2026. Annual gift exclusion: $19,000 per recipient. Estate exemption: $15,000,000 per person (OBBBA, 2025). Social Security benefit eligibility rules reflect current 42 U.S.C. § 402; Social Security Fairness Act (Jan. 2025) repealed WEP/GPO but did not extend spousal/survivor benefits to unmarried partners.