Common-Law Relationships in Ontario: A Complete Guide

What Counts as a "Common-Law Relationship" in Ontario?

Unlike marriage, no certificate or ceremony makes a couple "common-law." Whether a couple counts as common-law depends on which legal question is being asked, since Ontario's Family Law Act does not use one uniform definition of "spouse."

For support-related purposes, the Family Law Act generally treats two people as spouses if they are not married but have cohabited continuously for at least three years, or have cohabited in a relationship of some permanence and are parents of a child together. "Cohabit" generally means living together in a conjugal relationship, assessed on the overall nature of the relationship, not a single factor like a shared address.

This definition is not used everywhere in family law. As explained below, property division and the matrimonial home use a narrower meaning of "spouse" that generally requires marriage.

Common-Law vs. Married: The Key Legal Differences at a Glance

Many people assume that living together long enough creates the same rights as marriage. In Ontario, that is generally not accurate. Key differences include:

• Property division: Married spouses may get automatic equalization of net family property. Common-law partners generally do not.
• The matrimonial home: Special possessory protections apply only to married spouses, regardless of who is on title.
• Support: Common-law partners meeting the cohabitation threshold can generally claim spousal support like a married spouse.
• Parenting and child support: Handled the same way regardless of marital status.
• Ending the relationship: Married spouses need a divorce to remarry; common-law partners do not.

These distinctions matter most when a relationship ends, which is when many couples first learn how differently the law treats them.

Property Rights: Why Common-Law Partners Are Treated Differently

Ontario's Family Law Act gives married spouses a right, in most cases, to an equalization of net family property when the marriage ends — broadly, comparing what each spouse was worth at marriage and at separation, and requiring an equalizing payment. This scheme generally applies only to spouses who were legally married.

Common-law partners are generally not entitled to this automatic equalization, no matter how long they lived together. Property acquired during a common-law relationship generally belongs to whichever partner's name is on it, unless another legal basis for a claim applies. Read more about how property division works in Ontario.

This distinction is frequently misunderstood, and can come as an unwelcome surprise to long-term common-law partners who assumed the law treated them like a married couple.

Unjust Enrichment and Constructive Trust: How Common-Law Partners Can Still Claim Property

Because the Family Law Act's equalization scheme generally does not apply to common-law partners, courts rely on broader equitable principles to address unfairness when unmarried partners separate. Two related concepts come up most often: unjust enrichment and constructive trust.

In general terms, unjust enrichment can arise where one partner has been enriched — by gaining an interest in property, say — while the other suffered a corresponding loss, such as unpaid contributions of money or labour, with no legal reason for the imbalance. Where a court finds unjust enrichment connected to a "joint family venture" between long-term partners, a concept refined by the Supreme Court of Canada, it may order a monetary award reflecting each partner's contribution, or recognize a constructive trust giving them an actual share of a specific property.

These claims are generally more complex than a married spouse's equalization claim, and outcomes depend heavily on the evidence of each partner's contributions.

The Matrimonial Home Does Not Apply to Common-Law Partners

Ontario law gives special legal status to a couple's "matrimonial home," including equal possession rights regardless of ownership and restrictions on selling or mortgaging it without the other spouse's consent. These protections generally apply only to married spouses.

For common-law partners, there is generally no equivalent legal concept of a matrimonial home. A partner who is not an owner or named tenant generally has no automatic right to remain there or block a sale, regardless of how long the couple lived there together. Learn more about matrimonial home rules in Ontario.

A common-law partner who contributed to a home they do not own may still pursue an unjust enrichment or constructive trust claim, as discussed above, but this generally requires a court application rather than an automatic statutory right.

Child Support for Common-Law Parents

Child support works differently from property, and is generally not affected by whether the parents were married. Both the federal Divorce Act and Ontario's Family Law Act rely on the same Child Support Guidelines, and any parent — married or common-law — can generally seek child support for a child in their care.

A parent's obligation to support a child generally turns on the parent-child relationship itself, not marital status. Common-law parents typically face the same guideline-based approach to calculating support as married parents.

Spousal Support for Common-Law Partners

Unlike property division, spousal support is generally available to common-law partners who meet the Family Law Act's definition of spouse discussed above — broadly, at least three years of continuous cohabitation, or a relationship of some permanence with a child together. A partner meeting this threshold can generally seek spousal support on a similar basis to a married spouse, considering the length of the relationship, roles during it, and each partner's means and needs.

A partner who does not meet this cohabitation threshold generally has no claim to spousal support, which is one reason establishing the relationship's start date can matter a great deal in a common-law separation.

Parenting Time and Decision-Making Responsibility

Ontario's approach to parenting arrangements — including parenting time and decision-making responsibility — generally does not distinguish between married and common-law parents. Arrangements are generally decided based on the best interests of the child at the time the issue arises, not the parents' relationship status.

A common-law parent generally has the same standing to seek parenting time or decision-making responsibility, and the same obligations toward a child, as a married parent.

Cohabitation Agreements: Setting Your Own Rules

Because common-law partners generally do not have the same automatic property and home rights as married spouses, many couples put their own arrangements in writing through a cohabitation agreement. This type of domestic contract can generally address how property will be divided, how debts will be handled, and whether spousal support will be paid — subject to Ontario's general requirements for domestic contracts, such as being written, signed, and witnessed.

A cohabitation agreement generally cannot bind a court on parenting matters, since those issues are decided based on the child's best interests at the relevant time.

What Happens If You Separate Without an Agreement

Many common-law couples never sign a cohabitation agreement, meaning each partner's rights depend on general legal principles rather than a pre-arranged plan. In practice, this often means:

• Property generally stays with whoever legally owns it, absent a successful unjust enrichment or constructive trust claim.
• A partner who qualifies as a spouse for support purposes may still claim spousal support.
• Child support and parenting arrangements are addressed the same way as for married parents.
• Unresolved disputes generally need to go through family court or another dispute-resolution process.

Separating without an agreement does not mean a partner has no options — it generally means relying on broader legal doctrines and more evidence-gathering than a married spouse's equalization claim.

Common-Law Relationships and Wills & Estates

Common-law status can matter for some estate-related purposes, but this area is governed by separate legislation, and the specific rules are technical and can change. A surviving common-law partner does not automatically inherit from a deceased partner's estate the way a married spouse might in certain circumstances, particularly if there is no will.

Because the details are fact-specific, this guide deliberately avoids stating specific estate rules. Anyone who wants certainty about what happens to property after death should speak with a qualified professional about wills and estate planning rather than relying on assumptions.

Formalizing Rights: Agreements and Documentation

Given the gaps between common-law and married status, documentation generally plays an outsized role for common-law couples. Steps couples sometimes take include signing a cohabitation agreement, keeping records of financial contributions to shared property, holding significant assets in both names, and reviewing wills and beneficiary designations over time.

None of these steps is legally required, but each can reduce uncertainty later. A cohabitation agreement is generally the most comprehensive tool, letting a couple set their own rules in advance rather than relying on general legal doctrines afterward.

A General Step-by-Step Pathway If a Common-Law Relationship Is Ending

This is a general outline. Your own steps may vary depending on your situation and whether children or significant property are involved.

1. Confirm and document your separation date

   This date can matter for support and other time limits.

2. Gather financial information

   Property, debts, income, and records of contributions each partner made.

3. Check for an existing cohabitation agreement

   If one exists, it may already answer many property and support questions.

4. Identify whether you meet the spousal support threshold

   Generally three years of cohabitation, or a relationship of some permanence with a child together.

5. Address parenting arrangements separately

   Decided the same way regardless of marital status.

6. Consider whether a property claim may apply

   Such as unjust enrichment or constructive trust, if you contributed to property you do not own.

7. Get professional advice before signing anything

   Especially before giving up a potential claim or accepting a lump-sum settlement.

8. Put any resolution in writing

   A signed, witnessed agreement can help avoid disputes about what was agreed later.

Common Mistakes and Misunderstandings About Common-Law Rights

• Assuming years of living together automatically creates a 50/50 property split
• Believing matrimonial home rules apply simply because a couple shared a home
• Overlooking that spousal support and property division use different legal tests
• Not documenting the date the couple stopped living together
• Assuming a cohabitation agreement can decide parenting arrangements
• Waiting too long to get advice about a potential property claim
• Assuming common-law status automatically affects inheritance without checking the rules

Frequently Asked Questions