Common law marriage in Michigan is not available to couples today. State law has required a marriage license and a formal ceremony for any marriage to be legally valid since January 1, 1957.1Michigan Legislature. Michigan Compiled Laws 551.2 – Marriage as Civil Contract; Consent; License; Solemnization Two narrow exceptions survive: common law marriages formed in Michigan before that cutoff, and valid common law marriages formed in another state before the couple moved here. For everyone else, living together, sharing finances, and raising children together does not create a legal marriage no matter how many years go by.
The 1957 Cutoff and the Grandfather Exception
Michigan’s statute is forward-looking. It requires a license and solemnization for marriages on or after January 1, 1957, but it did not retroactively void common law marriages already in existence. A couple who established a valid common law marriage in Michigan before that date still has a legally recognized marriage.
As a practical matter, both partners would have needed to be adults at the time, which puts anyone in that category well over 80 years old today. The grandfather provision is largely historical and occasionally appears in estate disputes involving older family members. It is not a workaround for anyone who began cohabiting after 1957.
What the Old Rule Required
Where a pre-1957 marriage is at issue, Michigan courts look for three things. Both people had to agree, in the present moment, to be married to each other; a promise to marry later did not count. The couple had to live together. And they had to hold themselves out publicly as married through things like a shared last name, joint tax returns, or introducing each other as spouses. Both partners also had to be legally free to marry, meaning old enough and not already married to someone else.
Common Law Marriages Formed in Another State
If you formed a valid common law marriage in a state that allows it and then moved to Michigan, the state treats your marriage as legally valid. Michigan has a longstanding statutory framework for recognizing marriages lawfully created elsewhere.2Michigan Legislature. Michigan Compiled Laws Chapter 551 – Foreign Marriages The marriage has to have been fully established under that other state’s law before the move. Relocating to Michigan and then claiming a common law marriage based on a state you used to live in does not work.
A handful of jurisdictions still permit couples to form new common law marriages, including Colorado, Iowa, Kansas, Montana, Rhode Island, South Carolina, Texas, Utah, and the District of Columbia.3National Conference of State Legislatures. Common Law Marriage by State The specific requirements differ from state to state, and the law of the state where the marriage was formed controls whether it is valid.
If a common law marriage created elsewhere later breaks down, a Michigan court can grant the divorce. Standard residency rules apply: you or your spouse must have lived in Michigan for at least 180 days and in the county where you file for at least 10 days before filing the complaint.4Michigan Legislature. Michigan Compiled Laws 552.9 – Judgment of Divorce; Residency Requirements
Social Security follows the same logic for survivor benefits. The agency will honor a common law marriage only if it was valid under state law where it was formed, so a Michigan couple who never established a marriage in a state that allows it cannot qualify on that basis.5Social Security Administration. 20 CFR 404.726 – Evidence of Common-Law Marriage
What Unmarried Couples in Michigan Actually Face
Because common law marriage is not an option, the legal gap between long-term unmarried couples and married couples in Michigan is wide. It shows up in three places that matter most: inheritance, property, and children.
Inheritance: Zero by Default
If your unmarried partner dies without a will, you inherit nothing. Michigan’s intestate succession statute passes everything to the deceased person’s children first, then parents, then siblings, and on through more distant relatives.6Michigan Legislature. Michigan Compiled Laws 700.2103 – Share of Heirs Other Than Surviving Spouse An unmarried partner does not appear anywhere in that line, no matter how long you were together or how tangled your finances were. You could lose the home you shared, vehicles you helped pay for, and personal property you thought of as yours.
A will or trust fixes this, but only if it exists before the death occurs. For unmarried couples with any shared assets, this is the single most important legal document to put in place.
Real Estate and Joint Purchases
How you hold title matters. When an unmarried couple buys a home together, Michigan defaults to treating them as tenants in common. Each person owns a separate share that passes to their estate at death rather than to the surviving partner. To get automatic survivorship, the deed must specifically say joint tenants with right of survivorship.
If the relationship ends and one partner refuses to sell a jointly owned home, the other can file a partition action in circuit court to force a sale or physical division. It works, but it is slow, and attorney fees and court costs eat into whatever equity exists. There is no equivalent of the property-division framework that a divorcing couple would use. Each person keeps what is titled in their name, whoever actually paid for it.
Parental Rights
For unmarried couples with children, the birth parent who carried the child has sole custody by default. The other parent has no automatic legal rights to custody or parenting time, even after years of active parenting.7Michigan Legislature. Michigan Compiled Laws 722.1007 – Acknowledgment of Parentage Act
Signing an Affidavit of Parentage at the hospital establishes legal parentage but does not shift the custody default. What it does is give the other parent standing to ask a court for custody or parenting time, and it creates a support obligation on both sides. Either parent can then petition for a custody order. Without a signed affidavit, the non-birth parent typically has to file a paternity action first. Couples who are getting along rarely think about this. If the relationship ends without a custody order in place, the non-birth parent can find themselves locked out until a court steps in.
Documents That Fill the Gap
Without a marriage certificate, protection has to be built one document at a time. The gap is not theoretical. Hospital emergencies, sudden deaths, and unexpected breakups all happen, and each one exposes unmarried couples to problems married couples never face.
Wills and Trusts
A will lets you direct assets to your partner after death. A trust can go further by avoiding probate, keeping arrangements private and speeding up the transfer. For any unmarried couple who jointly owns a home or shares significant assets, an estate planning attorney is the practical starting point.
Cohabitation Agreements
A cohabitation agreement is a written contract covering how you and your partner handle property, finances, and debts during the relationship and after a breakup. It can address ownership, shared expenses, and what happens to jointly purchased property if you separate. Both parties must sign voluntarily with a clear understanding of the terms, and each partner should ideally have their own attorney review it.
Two hard limits. A cohabitation agreement cannot waive or cap child support; courts will not enforce provisions that shortchange a child regardless of what the parents agreed to. Agreements also fail if they condition financial support on companionship, which Michigan courts treat as unenforceable on public policy grounds.
Patient Advocate Designation
Michigan law allows any adult of sound mind to designate another adult to make medical and mental health treatment decisions on their behalf. The designation takes effect only when you become unable to participate in your own care. It must be in writing, signed, dated, and witnessed by two people who are not your spouse, parent, child, grandchild, sibling, presumptive heir, physician, or the designated advocate.8Michigan Legislature. Michigan Compiled Laws 700.5506 – Patient Advocate Designation
Without this document, your partner may have no recognized authority to make healthcare decisions for you. Michigan’s Public Health Code does give patients the right to communicate with and receive visits from any person they choose unless a doctor documents a medical reason to restrict it.9Michigan Legislature. Michigan Compiled Laws 333.20201 – Patient and Resident Rights Visitation is not decision-making authority, though. If you are unconscious and cannot choose your visitor, the patient advocate designation is what gives your partner a voice.
Durable Power of Attorney
A durable power of attorney covers financial decisions rather than medical ones, allowing your partner to manage bank accounts, pay bills, handle insurance, and deal with other financial matters if you become incapacitated. Under Michigan law, a power of attorney is durable by default unless it explicitly says otherwise, meaning your partner’s authority continues even after you lose the ability to make decisions yourself.10Michigan Legislature. Michigan Compiled Laws – Uniform Power of Attorney Act, Act 187 of 2023 It does not authorize medical decisions. You need both this document and a patient advocate designation to cover the full range of emergencies.