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Can You Bring an Unjust Enrichment Claim After a Short Common-Law Relationship in Ontario?

Ontario's cohabitation thresholds don't apply to unjust enrichment claims. Learn what you actually need to prove after a short common-law relationship.

Family Law5 min readTSLBy the Treadstone Law team · OntarioUpdated 2026-07
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Key takeaways
  • Ontario's Family Law Act sets a minimum period of continuous cohabitation (or a relationship of some permanence plus a child together) before an unmarried partner can qualify as a…
  • An unjust enrichment claim has three components, and length of relationship isn't one of them: 1.

A common assumption trips up a lot of separating couples: that you need to have lived together for a certain number of years before you have any property claim against a common-law partner. That assumption is only half right. Ontario's Family Law Act does set cohabitation thresholds — but they apply to spousal support, not to every kind of claim. An unjust enrichment claim runs on entirely different rules, and a short relationship doesn't automatically shut the door on it.

If you made a significant financial or non-financial contribution during a relationship that didn't last long, it's worth understanding what unjust enrichment actually requires before assuming you have no options.

The Common Misconception: "We Weren't Together Long Enough"

Ontario's Family Law Act sets a minimum period of continuous cohabitation (or a relationship of some permanence plus a child together) before an unmarried partner can qualify as a "spouse" for spousal support purposes. That threshold is real, but it's specific to support claims.

Property claims between unmarried partners work differently. Ontario has no equivalent statutory threshold for unjust enrichment. The doctrine comes from general legal principles about fairness, not from a cohabitation-length rule, so a short relationship doesn't disqualify a claim on its own.

The Three Elements You Actually Need to Prove

An unjust enrichment claim has three components, and length of relationship isn't one of them:

  1. Enrichment — your former partner received a benefit (money, property, unpaid labour, increased equity in an asset)
  2. Corresponding deprivation — you gave up something of value to provide that benefit
  3. No juristic reason — there's no legal reason (like a valid gift, a contract, or a legal obligation) that explains why your partner should keep that benefit without compensating you

If you can point to specific facts supporting each of these, the length of the relationship becomes just one factor among many — not a gatekeeper.

How This Differs From Ontario's Support and Property Rules

Claim typeGoverning ruleMinimum relationship length required?
Spousal support (unmarried partners)Family Law Act "spouse" definitionYes — a minimum cohabitation period, or a relationship of some permanence plus a child
Equalization of net family propertyFamily Law Act (married spouses only)Not applicable — unmarried partners don't qualify regardless of length
Unjust enrichmentGeneral legal principles, not a fixed statuteNo fixed minimum

This table is one reason so much confusion exists: three different claims, three different rules, and only one of them cares how long you cohabited.

What Strengthens (or Weakens) a Short-Relationship Claim

Because there's no bright-line threshold, the strength of a short-relationship claim usually comes down to the specifics. Consider:

A short relationship with a large, well-documented, traceable contribution can be a stronger claim than a long relationship with vague, undocumented ones.

Frequently asked questions

How short is too short for an unjust enrichment claim?

There's no set minimum. Courts look at the substance of what happened — the contribution, the benefit, and whether it's fair for your former partner to keep it — rather than counting months or years as a threshold.

What if I just paid rent or household bills while we lived together?

Ordinary contributions to shared living expenses during cohabitation are often treated as the normal give-and-take of a relationship rather than an enrichment claim. A stronger claim usually involves something beyond day-to-day costs — a lump sum, unpaid work, or a contribution tied to a specific asset.

Can I get a share of an asset, or only money back?

Both are possible. Depending on the facts, a court can order a monetary award or, in some cases, declare that you hold an ownership interest in a specific property. Which remedy fits depends on your contribution and the asset involved.

Do I need to prove we were "common-law spouses" to bring this claim?

No. Unjust enrichment doesn't require you to meet any spousal definition at all — it's available between any two people, including unmarried partners, regardless of whether they meet a support-related cohabitation threshold.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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