Can My Common-Law Partner Take My House in Ontario?

No — not automatically. In Ontario, common-law partners have no automatic right to share property at separation, regardless of how long they've lived together. If the house is in your name only, you own it. But "automatically" is doing a lot of work in that sentence. After years of cohabitation, your partner may have a real legal claim to a share of your home through unjust enrichment — and pursuing or defending against that claim costs $50,000–$100,000 or more in legal fees with no guaranteed outcome. A cohabitation agreement is the only thing that settles this clearly for both of you before it becomes a problem.

The rule: what's in your name is yours

Ontario's Family Law Act — the statute that governs property division for married couples — does not apply to common-law partners. Part I of the Family Law Act R.S.O. 1990, c. F.3, which creates the net family property equalization regime, applies only to married spouses. Common-law couples are not included.

This means:

• If the house is in your name only, your partner has no automatic legal right to a share of its equity — not after 3 years, not after 10 years, not after 20 years.
• Your partner has no automatic right to live in the home at separation. There are no "matrimonial home" possession rights for common-law couples.
• Your partner has no automatic right to a share of other property you own — savings, investments, business equity — regardless of how long you lived together.

The contrast with a married couple is stark. If a married person owns a home that becomes the matrimonial home, their spouse has both a statutory right to live there and a right to share in equalization of its full value at separation. None of this applies to common-law couples in Ontario.

Approximately 50–60% of Canadians incorrectly believe common-law partners have the same property rights as married spouses. In Ontario, this belief is not a partial truth — it's simply wrong.

The exception: unjust enrichment and constructive trust

Here's where the "automatically" matters. Your partner may not have automatic rights, but they may have legal claims — and those claims can be substantial after long cohabitation.

Under Kerr v. Baranow [2011] SCC 10, the Supreme Court of Canada established that common-law partners can claim a share of property through unjust enrichment. To succeed, the claimant must prove three elements:

Enrichment. You were enriched — your home's equity increased, your wealth grew, your career advanced — at least partly because of contributions your partner made.

Corresponding deprivation. Your partner suffered a corresponding loss — they paid toward the mortgage, funded renovations, provided unpaid domestic labour that freed you to build your career and wealth, or gave up their own career advancement.

No juristic reason. There's no contract or other legal reason justifying the enrichment — no agreement that their contributions were intended as rent, gifts, or shared expenses.

If unjust enrichment is established, courts may award a monetary remedy or, in more serious cases, impose a constructive trust — a court order declaring that your partner has an actual ownership interest in the property.

The joint family venture doctrine from Kerr v. Baranow extends this further. Where a couple can demonstrate mutual effort, economic integration, shared intent, and a focus on the family's wellbeing, courts may award a share of the overall wealth gained during the relationship rather than just compensation for specific contributions. This can result in claims that go well beyond what individual contributions would justify.

What counts as a contribution in practice:

• Mortgage payments — even if made informally, even if understood by both parties to be "rent"
• Renovation labour and costs
• Unpaid domestic work, childcare, and household management that freed the titled partner to focus on income and career
• Foregone career opportunities to support the relationship

The uncomfortable reality: "Your honour, I paid half the mortgage" — "That was rent" is the exchange quoted across Canadian Reddit for good reason. In Ontario, informal mortgage contributions don't create automatic legal ownership. They may support an unjust enrichment claim. But that claim requires expensive litigation, takes years, and has no guaranteed outcome.

What the litigation actually costs

Pursuing an unjust enrichment claim through Ontario courts typically costs $50,000–$100,000 or more in legal fees. The process can take two to five years. The outcome is inherently uncertain — courts weigh fact-specific evidence about the nature and value of contributions, the degree of economic integration, and whether the three-part unjust enrichment test is met.

This uncertainty cuts both ways:

If you own the home: even if you're legally in the right, defending an unjust enrichment claim after a long relationship costs tens of thousands of dollars and years of your life. Winning is not free.

If your partner owns the home: even if you contributed substantially to a shared life in a home where you had no title, litigation is expensive, slow, and uncertain. You may win. You may not. You will spend significantly to find out.

A 2025 Ontario case, Byrne v. Milner, illustrates the real-world stakes: after 15 years of cohabitation, one partner successfully claimed an interest in the other's home based on renovation contributions and economic integration, despite not being on title. The joint family venture doctrine was central to the court's analysis — the depth of financial integration over 15 years shifted the outcome significantly compared to a shorter relationship.

Both parties lose compared to having had a cohabitation agreement.

How this compares to BC and other provinces

Ontario is at one extreme of the Canadian spectrum. In British Columbia, since 2013 reforms to the Family Law Act SBC 2011, common-law couples have near-equal property division rights after 2 years of cohabitation — property acquired during the relationship is divided, pre-relationship property is excluded. British Columbia and Saskatchewan are the only provinces with full statutory common-law property division.

Alberta offers limited rights for "adult interdependent partners" after 3 years, but these fall short of equal property division. Quebec offers nothing — no property rights and no support rights for common-law couples, a position the Supreme Court upheld in Quebec (Attorney General) v. A [2013] SCC 5.

Ontario sits with the majority of provinces: no automatic property rights regardless of how long you've lived together. If you've recently moved from BC to Ontario, your legal situation has changed materially even if your relationship hasn't.

What a cohabitation agreement does

A cohabitation agreement is a domestic contract under Part IV of the Family Law Act — the same framework as a marriage contract, but for unmarried couples. It fills the gap the law leaves open by providing a "juristic reason" that defeats unjust enrichment claims before they arise.

What a properly drafted cohabitation agreement establishes:

Who owns what. Each party's ownership of their separate property is defined clearly — the house in your name is yours; contributions during the relationship don't create ownership rights.

How contributions are treated. Mortgage payments, utility payments, and renovations are defined as shared household expenses or rent rather than equity-building contributions. This is the clause that closes the unjust enrichment door.

What each person is entitled to at separation. If you've built something together, the agreement can define that too — including how jointly acquired property is treated if you eventually buy together.

What happens to spousal support. Under FLA s. 29, common-law support eligibility begins after 3 years of cohabitation (or any period with a child). A cohabitation agreement can define how support is structured, including amounts, duration, and review triggers.

If you later marry. A cohabitation agreement can typically be confirmed or updated into a marriage contract, maintaining the core property arrangements and recalibrating them to the married-couple regime. The agreement you sign now doesn't need to be redone from scratch when you marry.

For a full explanation of what a cohabitation agreement covers in Ontario, including what the law says about common-law property rights and the three-part unjust enrichment test, that article covers the legal framework in detail.

Frequently Asked Questions

Can my common-law partner claim my house after 3 years in Ontario?

The 3-year threshold under Ontario's Family Law Act creates spousal support eligibility only — it gives no property rights. Your partner has no automatic claim to your house after 3, 5, or 15 years of cohabitation unless your name is on the title. What they may have after a long relationship is an unjust enrichment claim based on contributions made — which requires litigation, costs $50,000–$100,000+, and has no guaranteed outcome.

What if my partner paid toward the mortgage for years?

Informal mortgage contributions don't create legal ownership in Ontario. They may support an unjust enrichment claim at separation — but pursuing that claim is expensive and uncertain. A cohabitation agreement that defines how contributions are treated at the outset is substantially more predictable for both parties. Without one, both sides face the risk of litigation over whether those contributions create an equitable interest.

Does it matter whose name is on the title?

Yes — significantly. In Ontario, the person on title owns the property. A common-law partner not on title has no automatic right to a share of the equity. Title is not the end of the story — unjust enrichment claims can succeed even where the claimant isn't on title — but title determines the default legal position.

Can I protect my house by not putting my partner's name on it?

Keeping your name on title protects you from automatic property sharing — Ontario law won't give your partner a share just because they lived there. But it doesn't protect you from an unjust enrichment claim if your partner made substantial contributions over a long relationship. The protection against such claims is a cohabitation agreement that provides a juristic reason — a contract clearly stating that contributions don't create ownership rights. Title alone is not sufficient.

What if we break up — can my partner force a sale?

If the house is in your name only, your partner has no right to force a sale without first establishing a legal claim through litigation. If they successfully establish a constructive trust, a court can order remedies including a declaration of ownership interest. If you're joint owners, either party can typically seek a partition and sale if you can't agree on a buyout. A cohabitation agreement can define what happens to a jointly owned property at separation.

Is a cohabitation agreement the same as a prenup?

Almost. A cohabitation agreement is a domestic contract under Part IV of Ontario's Family Law Act — the same legislative framework that governs marriage contracts. The primary difference is timing: a cohabitation agreement is signed when you're not yet married. If you later marry, it can typically be updated or confirmed as a marriage contract. The enforceability requirements are the same: written, signed, witnessed, with full financial disclosure and independent legal advice for both parties.

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This article provides general information about Ontario family law and does not constitute legal advice. For advice specific to your situation, consult a licensed Ontario family lawyer.