Common Law vs. Marriage in Ontario: Key Differences
Living together is not the same as being married in Ontario. The legal gaps can cost you — here’s exactly what changes and what doesn’t.
Reviewed by
Deepa Tailor — Senior Family Lawyer, Tailor Law
“The most common mistake I see is common law couples assuming they have the same rights as married spouses. They don’t — especially on property. A cohabitation agreement is not just for wealthy couples; it’s essential protection for anyone who owns a home or has significant assets.”
30-Second Answer
In Ontario, married spouses have automatic rights to equalization of net family property and the matrimonial home. Common law spouses do not — they must rely on constructive trust claims or written agreements. Both statuses trigger spousal support rights after 3 years of cohabitation (or sooner with a child). The gap is biggest on property: married spouses split the growth in wealth; common law spouses keep only what they can prove they own or contributed to.
Side-by-Side Comparison
The differences that matter most — especially on separation.
| Topic | Married Spouses | Common Law Spouses | Risk Gap |
|---|---|---|---|
| Property Division | Automatic equalization of Net Family Property under the Family Law Act | No automatic right — must prove ownership or constructive trust | high |
| Matrimonial Home | Both spouses have equal right to possession regardless of whose name is on title | Only the registered owner has the right to stay — no automatic protection | high |
| Spousal Support | Entitlement arises on separation regardless of length (though duration matters) | Entitlement after 3 years cohabitation, or sooner if a child is born | medium |
| Inheritance (Intestacy) | Surviving spouse receives preferential share under the Succession Law Reform Act | No automatic inheritance — must be named in a will or sue under dependant’s relief | high |
| Pension Division | Pension value included in NFP equalization calculation | No automatic pension division — must negotiate or litigate | high |
| Child Support | Same rules apply under the Child Support Guidelines | Same rules apply — no difference | low |
| Child Custody / Parenting | Governed by Divorce Act or CLRA depending on whether divorce is filed | Governed by Children’s Law Reform Act — same best interests test | low |
| Name Change | Can take spouse’s name upon marriage | No automatic name change right | low |
| Tax Benefits | Spousal RRSP contributions, pension income splitting | Same tax treatment after 12 months cohabitation (CRA definition) | low |
| Protection Agreement | Marriage contract (prenup/postnup) | Cohabitation agreement — strongly recommended | medium |
The Property Gap: The Biggest Risk for Common Law Couples
This is where common law couples are most exposed. Understanding the difference could save — or cost — hundreds of thousands of dollars.
Married Spouses
- Each spouse calculates their Net Family Property (NFP)
- The spouse with the higher NFP pays the other half the difference
- Applies to ALL property acquired during the marriage
- The matrimonial home is fully included — even if inherited
- Automatic — no need to prove contribution
Common Law Spouses
- No automatic equalization — each keeps what is in their name
- Must prove a constructive or resulting trust to claim a share
- Must show unjust enrichment: you contributed, they benefited, no legal reason for the gap
- The home belongs to whoever is on title — full stop
- Litigation is expensive and uncertain without a cohabitation agreement
The Fix: A Cohabitation Agreement
Common law couples can contractually replicate many of the protections married spouses have automatically. A properly drafted cohabitation agreement sets out what each party owns, how property will be divided on separation, and spousal support obligations — giving both partners certainty and protection.
Frequently Asked Questions
Deepa Tailor
Senior Family Lawyer
Deepa Tailor advises both married and common law couples on protecting their financial interests — from cohabitation agreements to complex property disputes on separation.
Common Law or Married — Know Where You Stand.
Don’t discover the gaps on separation. Get a clear picture of your rights and protect what matters most with a properly drafted agreement.