Common-Law Relationships vs. Marriage in Ontario: Key Legal Differences

Many couples in Ontario live together without getting married. But the legal consequences of separating from a common-law partner are very different from divorcing a married spouse. Understanding these differences is critical — and many couples do not find out until it is too late.

Who Qualifies as a Common-Law Partner in Ontario?

In Ontario, for the purposes of most family law rights, a common-law couple is two people who:

• Have lived together in a conjugal relationship for at least 3 continuous years, or
• Have lived together in a relationship of some permanence and have a child together

Note: The threshold varies depending on which law applies (Ontario Family Law Act vs. federal Divorce Act for married couples). Cohabitation rights under the FLA require the 3-year or child threshold.

The Critical Difference: Property Rights

This is the most important difference between married and common-law couples.

Married Spouses

Married spouses benefit from Ontario’s equalization of net family property system. When a marriage breaks down, each spouse is entitled to share equally in the wealth accumulated during the marriage. The spouse with the higher NFP pays the other half the difference.

This means that even if one spouse earned all the income and holds all the assets in their name, the other spouse has a legal claim to equalization.

Common-Law Partners

Common-law partners have no right to equalization of net family property under the Ontario Family Law Act.

Property belongs to whoever legally owns it. If one partner owns the house and the other does not have their name on title, the non-titled partner generally has no automatic right to share in the home’s value.

This is a stark difference. A spouse of 20 years who contributed to the household and supported their partner’s career — but whose name is not on any asset — may walk away from a common-law relationship with nothing.

Can Common-Law Partners Claim Anything?

Yes — but the claims are different and harder to establish:

Unjust Enrichment / Constructive Trust

A common-law partner who contributed to the acquisition or improvement of the other partner’s assets (financially or through domestic contributions) may be able to claim unjust enrichment. If successful, the court may impose a constructive trust on the asset, giving the claimant a beneficial interest.

This requires litigation and evidence of:

• The other party was enriched
• The claimant was deprived
• There is no juristic reason for the enrichment

These claims are not guaranteed and can be costly to pursue.

The Matrimonial Home: Not Available to Common-Law Partners

Married spouses have equal possession rights to the matrimonial home, regardless of who owns it. Neither spouse can unilaterally sell it.

Common-law partners have no such protection. The partner whose name is on title can sell the home — in principle — without the other’s consent.

Spousal Support: Available to Common-Law Partners

Unlike property division, spousal support is available to common-law partners — provided they meet the cohabitation threshold. The entitlement analysis and calculation is similar to that for married spouses.

Children: No Difference

The parenting and child support rights of common-law parents are identical to those of married parents. Child support is calculated the same way under the Federal Child Support Guidelines, regardless of whether the parents were married.

The Solution: A Cohabitation Agreement

The most effective way for common-law couples to protect themselves is a cohabitation agreement. This is a legally binding contract that addresses:

• How property is owned and how it will be divided on separation
• Whether support will be paid, and how much
• How shared expenses are managed during the relationship

A cohabitation agreement should be signed before moving in together — or as soon as possible after. It requires full financial disclosure and independent legal advice for each party to be enforceable.

If the couple later gets married, a cohabitation agreement typically converts into a marriage contract.

Practical Advice

Do not assume that living together for years gives you the same legal rights as being married. It does not — particularly with respect to property.

If you are in a common-law relationship and have not signed a cohabitation agreement, consider doing so now. If you are separating from a common-law partner and believe you have an unjust enrichment claim, act quickly — limitation periods apply.

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This article was written by Miao He (何淼), Ontario lawyer (LSO #83315K) and China-licensed lawyer, focusing on family law for the Chinese-Canadian community in the GTA.