- Ontario does not divide property between unmarried couples when they separate, so each partner generally keeps what they bought.
- A cohabitation agreement can deal with property and support, but it is unenforceable unless it is in writing, signed and witnessed.
- Even a valid agreement has limits: a court can set parts of it aside in certain situations, and child-related terms are never fully locked in.
You are about to move into a home your partner already owns. You may plan to help with the mortgage, pay for renovations, or simply share the bills, and you may wonder what any of that means for you if the relationship ends.
A cohabitation agreement is one way to answer those questions in writing before anyone unpacks a box. This article explains what it can cover, how to make it valid and where its limits are. It is general information, not advice about your situation.
Where you stand without an agreement
Under the Family Law Act, the word "spouse" in the property division and matrimonial home parts means people who are married to each other. It does not include unmarried partners. Ontario does not divide property between common-law couples when they separate. Each partner keeps the property they bought, and neither has a right to share in the other's increase in property value.
Furniture, household items and other property belong to the person who bought them. The special protections for a matrimonial home also do not cover unmarried partners. In plain terms, moving into your partner's house does not by itself give you ownership of it or a protected right to stay.
There is an exception for contributions. A common-law partner who contributed to property the other owns may have a right to part of it. Unless the owner agrees to pay the contribution back, the partner may have to go to court. A written agreement lets you settle that question early instead of arguing about it later.
What a cohabitation agreement can cover
Two unmarried people who are cohabiting, or who intend to cohabit, may make a cohabitation agreement about their rights and obligations, including property and support. Because you have not moved in yet, you fit the "intend to cohabit" situation.
Topics couples in your position often want to put in writing include:
- That the home stays your partner's property and that moving in does not change who owns it.
- How any money you put toward the mortgage, property taxes, repairs or renovations will be treated, for example as a loan to be repaid, a credit, or a share of living costs.
- Who owns the furniture, vehicles and other items each of you brings.
- How household expenses will be split while you live together.
- How long you may stay, and for how long after a separation, if you want to address that.
- Whether either of you gives up or sets terms for support.
Which terms make sense depends on your finances and plans, so treat the list as a set of questions to discuss, not a template.
Making the agreement valid
A domestic contract, including a cohabitation agreement, is unenforceable unless it is in writing, signed by the parties and witnessed. Ontario's guidance says both partners must sign in front of a witness. It also advises that each partner speak to a different lawyer and that you exchange financial information before signing.
That financial exchange matters. Failing to disclose significant assets or debts can later be a reason for a court to set a contract aside. If you later marry each other, the cohabitation agreement is deemed to be a marriage contract.
What an agreement cannot fully lock in
| Topic | What the law says |
|---|---|
| Property and support between you | Can be covered by the agreement. |
| Children's education and moral training | Can be covered. |
| Decision-making responsibility and parenting time | Cannot be dealt with in a cohabitation agreement. |
| Child support | A court may disregard a provision that is unreasonable under the child support guidelines. |
A cohabitation agreement may deal with a child's education and moral training, but a court deciding those questions may disregard a provision about them if that is in the child's best interests. The same best-interests power applies to decision-making responsibility and parenting time when a court decides them.
For support, a court may set aside a support provision or waiver if it results in unconscionable circumstances, if the dependant qualifies for support out of public money, or if support under the contract is in default when the application is made. A court may also set a contract aside if a party did not understand its nature or consequences.
What to do before you move in
- Gather the home's ownership details, the mortgage balance and your own savings, debts and income.
- List what you expect to contribute and what you expect in return.
- Decide whether you want terms on how long you can stay if you separate.
- Exchange complete financial information with your partner.
- Each arrange to speak with a separate lawyer.
- Sign in front of a witness before you move in, and keep a copy each.
Starting early, while the relationship is warm, usually makes for a calmer conversation than waiting until money has already changed hands.
Frequently asked questions
Do I get a share of my partner's house just by living there?
Not automatically. Ontario does not divide property between common-law couples, and each partner keeps what they bought. If you contributed to property your partner owns, you may have a right to part of it, but you may have to go to court to claim it.
Can we sign the agreement after I move in?
Yes. The law allows an agreement between unmarried people who are cohabiting or who intend to cohabit. Signing before you move in simply settles the terms before contributions are made.
Does the agreement need a witness?
Yes. A domestic contract is unenforceable unless it is in writing, signed by the parties and witnessed. Ontario's guidance also advises that each partner speak to a different lawyer.
What happens to the agreement if we marry?
If the parties to a cohabitation agreement later marry each other, the agreement is deemed to be a marriage contract. It is worth reviewing the terms at that point.
Sources
- Family Law Act, R.S.O. 1990, c. F.3 (e-Laws) — Ontario e-Laws
- Ontario.ca – Dividing property when a marriage or common law relationship ends — ontario.ca
Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.
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