Should Unmarried Couples Have a Cohabitation Agreement?

More couples are living together, buying homes, raising children, and building financial lives together without marrying. California law does not give unmarried partners the same financial protections and obligations that married couples get. It does allow unmarried partners to make enforceable agreements about property and support, but without something in writing, those agreements are much harder to prove. A cohabitation agreement lets a couple set the rules while they are together, rather than asking a court to reconstruct their intentions after the fact.

What is a cohabitation agreement?

It's a contract between unmarried partners covering their financial rights and responsibilities: what each person owns separately, how property acquired during the relationship is treated, how expenses are shared, what happens to a home bought together, and whether either partner owes the other support if the relationship ends. It does for an unmarried couple what a premarital agreement does for a couple planning to marry: it sets the financial rules before there's a dispute about what those rules were.

Why does an unmarried couple need one?

Marriage comes with a body of law governing property and support. Living together doesn't. Ten or twenty years together doesn't turn what you acquire into community property, and California doesn't simply split everything down the middle when an unmarried couple separates. Ownership instead depends on whose name is on title, who contributed what, and whether the couple made any agreement, spoken or implied. That surprises a lot of people, especially after years of functioning financially like a married couple.

What happens if we don't have one?

A breakup can turn into a dispute over what the partners actually promised each other. California law lets unmarried partners enforce agreements about property and support even without a writing, including agreements implied from how the couple behaved. Spoken agreements are hard to prove because it comes down to one person's word against the other's. Implied agreements are harder still: a court has to look at conduct like joint bank accounts and credit cards, joint title, tax returns filed as married, beneficiary designations, and wills naming the other partner, and decide whether all of that adds up to an unspoken agreement to share.

Sorting that out can mean digging through years of financial records, texts, emails, and cards, and asking friends or family to testify about conversations from years earlier. It's also a fight that, unlike divorce, comes with no automatic right to support while the case is pending and no ability to recover attorney's fees from the other side, which can make it a genuinely expensive problem for whichever partner has less money and nothing in their own name. A cohabitation agreement avoids all of it.

We're buying a house together. Is that a reason to have one?

Yes, a home is often the single biggest reason. Say one partner puts $300,000 toward the down payment and the other puts in $50,000, both go on title, and they split the mortgage and improvements from there. If they separate five years later: does each get half the equity because they're equal owners on title? Does the bigger contributor get that money back first? How is appreciation split? Who keeps the house, and who pays the mortgage while that gets decided?

Those questions are far easier to answer if the couple sets the rules at purchase. The same issue comes up when only one partner is on title but the other pays toward the mortgage or renovations: is that rent, a gift, a reimbursable contribution, or an ownership stake? Without an answer in writing, a partner who isn't on title can also end up facing an eviction action to force them out of the home while the ownership dispute over that same property is still being litigated somewhere else.

What if one of us stays home with the kids?

This is another place a written agreement matters most. One partner may cut back hours, leave a career, or take on the household and childcare while the other keeps working and building income and assets. Married couples have a statutory framework for property and spousal support if they divorce; unmarried couples don't get that automatically, and a court has no authority to order interim support while an unmarried couple's dispute is being sorted out. A cohabitation agreement can spell out in advance what the couple intends if one partner makes that kind of sacrifice for the family.

Can it provide for support after separation?

Yes. Partners can agree to support each other after separation, or agree that neither owes the other anything. The point is deciding it while things are amicable, instead of one person claiming years later that support was promised and the other denying it.

What should it cover?

It should be tailored to the couple. Depending on circumstances, it can address property each partner already owns, income earned during the relationship, bank and investment accounts, how household expenses are split, real estate bought together or contributions toward a home owned by only one partner, a business created or run during the relationship, debts, gifts between partners, support after separation, what happens if one partner leaves the workforce for childcare, and how jointly owned property gets divided if things end. For couples with real estate, a business, savings, or a real income gap, these questions become financially significant quickly.

Is this only for wealthy couples?

No. The need has less to do with wealth than with how financially entangled the couple has become. A couple buying a $900,000 home with unequal down payments has good reason for an agreement even if neither considers themselves wealthy, and so does a couple where one partner moves into a home the other owns and starts covering real expenses, or where one partner leaves the workforce to raise children. The more intertwined the finances, the more useful it is to spell out what those arrangements actually mean.

What if we later decide to marry?

Revisit the agreement. Marriage changes the legal framework entirely. A couple planning to marry can sign a premarital agreement addressing finances going forward, and if they've already lived together for years, that agreement can also clarify what they understood about property from the unmarried years, before marriage changes the rules.

Isn't asking for one unromantic?

It doesn't have to be. Most couples already make financial agreements with each other informally: who pays the mortgage, whether to combine accounts, how much each person puts toward a house, whether one partner can stop working, whether money that passes between them is a gift or a loan. A cohabitation agreement just makes those decisions explicit and enforceable.

The alternative isn't having no agreement. It's leaving a court to decide years later whether one existed, based on what you said and did while you were still together. For couples building a financial life without marrying, putting the understanding in writing gives both people real clarity about what they're building, and what stays their own.