Constructive Trust and Unjust Enrichment Claims for Common-Law Partners in Ontario

When a common-law relationship ends in Ontario, many people are surprised — and devastated — to learn that the property rules that apply to married spouses simply do not apply to them. If your name is not on the deed to the house, the house is not automatically half yours, no matter how many years you lived there, raised children there, or helped pay for it. This is one of the most painful gaps in Ontario family law.

But that does not mean you are without options. Two related legal doctrines — unjust enrichment and constructive trust — give Ontario courts the power to recognize your contributions and award you a share of property you don't legally own. These are not simple claims to make, but they exist precisely because the law recognizes that strict title rules can produce deeply unfair outcomes.

This article explains how those doctrines work, what you need to prove, and why a cohabitation agreement remains the smarter path when the relationship is still good.

Why Common-Law Partners Don't Have the Same Property Rights as Spouses

Married spouses in Ontario benefit from the Family Law Act's equalization regime, which divides the growth in net family property between them when a marriage ends. Common-law partners are not covered by that regime. Their property rights depend on whose name is on title, whose name is on the account, and — critically — on equitable claims that must be won in court rather than assumed by law.

This distinction catches people off guard. A couple may have lived together for a decade, shared finances, bought a home together in one partner's name for practical reasons, and built a life together in every meaningful sense. None of that automatically creates a legal property right for the partner whose name is missing from the title documents.

Unjust Enrichment: The Core Claim in Plain English

Unjust enrichment is the legal way of saying: one person has been unfairly enriched at another person's expense, and the law should do something about it.

To succeed in a claim for unjust enrichment, a court must find three things:

1. Enrichment of the defendant — your partner received a benefit. This could be equity built up in a home, savings accumulated because your unpaid domestic labour freed them to work, or the direct value of money or work you contributed.

1. Corresponding deprivation of the claimant — you suffered a loss or gave something up. If you spent years managing the household, raising children, or working in a family business without pay, you gave up economic opportunities and contributed value that benefited your partner.

1. No juristic reason for the enrichment — there is no legal justification for your partner to keep the benefit without compensating you. A juristic reason might be a valid contract that explains the arrangement, or a gift you clearly intended to make. If there is no such reason, the enrichment is "unjust" in the eyes of the law.

All three elements must be established. Satisfying each one requires evidence — financial records, witnesses, documentation of your contributions over time.

What Is a Constructive Trust?

If a court finds unjust enrichment, it must then decide on a remedy. One powerful remedy is the constructive trust.

A constructive trust is a court order that says: even though title to this property is in your partner's name, a portion of it is held in trust for you. In practical terms, it can mean the court recognizes you as having a proprietary interest in a home, a business, or another asset — and orders that your interest be paid out or transferred to you.

Courts do not impose a constructive trust automatically. They use it when a monetary award would be inadequate — for example, when the property has increased in value and a simple cash payment would not reflect that gain, or when the claimant has a genuine connection to the specific asset in question.

The alternative remedy is a straightforward monetary award — a payment representing the value of what was unfairly retained. Courts choose between these remedies based on the circumstances of each case.

The Joint Family Venture Framework

Canadian courts have developed an important refinement of the unjust enrichment analysis through a concept known as the joint family venture. The idea, developed in a leading Supreme Court of Canada decision from the early 2010s, is that some common-law relationships look and function like joint economic partnerships — the partners pool their efforts, share goals, integrate their finances, and work together toward shared family objectives.

Where a court finds that a couple was operating as a joint family venture, it becomes easier to establish both enrichment and deprivation, and the remedy can be proportional to each partner's overall contribution to the venture rather than tied to specific, traceable transactions.

Courts look at a range of factors when assessing whether a joint family venture existed:

• Mutual effort — did the partners work together toward shared goals, including raising children or building household stability?
• Economic integration — were finances pooled, debts shared, and major decisions made jointly?
• Actual intent — did the parties treat themselves as partners in a meaningful sense?
• Priority of the family — did one partner subordinate their own career or financial interests for the benefit of the household?

This framework is important for partners who made non-financial contributions. Homemaking, childcare, supporting a partner's career, and managing the household are contributions that may not appear on a bank statement but are recognized under this analysis.

What Kinds of Contributions Count?

Both financial and non-financial contributions matter. Courts have recognized:

• Direct payments toward a mortgage, renovation, or purchase price
• Unpaid labour in a partner's business
• Homemaking, cooking, and household management over many years
• Primary caregiving for children, which enabled the other partner to focus on their career
• Giving up employment or career advancement to relocate or support the family

The key is evidence. Vague assertions that you "contributed to the household" will not carry a claim. Strong cases are built on documentation: financial records, testimony from people who observed the arrangement, calendars, photographs, tax returns, and anything else that shows what you actually did and what it was worth.

Why These Claims Are Difficult — and Expensive

Unjust enrichment and constructive trust claims are among the most complex and costly in family law. A few reasons:

• They are fully litigated. Unlike equalization claims between married spouses, which follow a statutory formula, these claims require a court to evaluate years of conduct, financial records, and contested facts. That means more lawyer time and more court time.
• Outcomes are uncertain. The analysis is fact-specific and discretionary. Two similar relationships may produce different results depending on how the evidence is presented.
• Quantifying contributions is difficult. How do you assign a dollar value to ten years of caregiving? Experts may be needed, which adds cost.
• Time limits apply. Limitation periods govern when a claim must be started — as of writing, verify current rules with a lawyer, as these can be affected by when you knew or ought to have known about the claim.

The best protection, by far, is a cohabitation agreement signed before or early in the relationship. A well-drafted agreement specifies what happens to property if the relationship ends, eliminates ambiguity, and costs a fraction of what litigation will.

Frequently asked questions