- Under the Family Law Act, married spouses benefit from an equalization of net family property regime — a formula that shares the growth of wealth during the marriage.
- A cohabitation agreement can address: - Property ownership — which assets belong to which partner, how jointly used assets are treated, and how property will be divided if the…
- Like a marriage contract, a cohabitation agreement cannot pre-settle parenting arrangements or child support.
Many Ontario couples live together for years — sometimes decades — without getting married. They buy homes together, build savings, raise children, and intertwine their financial lives completely. What many of them do not realize is that Ontario's property-division laws, which give married spouses significant financial protections on separation, generally do not apply to unmarried common-law couples.
A cohabitation agreement ontario fills that gap. It is a legal contract that lets unmarried partners define their financial rights and responsibilities — giving each other protections that the law does not automatically provide, or clearly setting out who owns what to avoid disputes later.
Common-Law Couples and the Property Gap
Under the Family Law Act, married spouses benefit from an equalization of net family property regime — a formula that shares the growth of wealth during the marriage. Common-law partners do not have access to this regime.
When a common-law relationship ends, each person generally walks away with what is in their name. If one partner owns the house, they keep it. If one partner's name is on an investment account, those funds belong to them. The other partner has limited legal recourse unless they can prove a constructive or resulting trust — essentially arguing that they contributed to the asset in a way that makes it unfair for the titled partner to keep it all. These claims are complex, expensive, and uncertain.
This means a common-law partner who contributed years of unpaid domestic work, supported their partner's career, or co-financed a home purchase may have very little to show for it at the end of the relationship — unless they have a cohabitation agreement or can mount a successful trust claim.
What a Cohabitation Agreement Can Do
A cohabitation agreement can address:
- Property ownership — which assets belong to which partner, how jointly used assets are treated, and how property will be divided if the relationship ends
- The family home — who has the right to live in the home during the relationship and what happens to it on separation, including how the equity is shared or who buys the other out
- Financial contributions — how household expenses, mortgage payments, and joint investments are shared and accounted for
- Debts — who is responsible for existing debts and debts incurred during the relationship
- Spousal support — whether either partner will pay support if the relationship ends, and how much or for how long (subject to some limits)
- Business interests — protecting a business owned by one partner from being shared
- Inheritances and gifts — confirming that these remain the receiving partner's separate property
The agreement can be protective in either direction. A partner with significant assets may want the agreement to confirm those assets remain theirs. A partner with fewer assets may want the agreement to guarantee them a share of property they helped build. Both uses are legitimate.
What a Cohabitation Agreement Cannot Do
Like a marriage contract, a cohabitation agreement cannot pre-settle parenting arrangements or child support. Courts will not enforce provisions that try to determine in advance who will have parenting time, who will make decisions about future children, or how much child support will be paid. These matters are governed by the best interests of the child at the time of any dispute, and parents cannot contract away children's rights.
The Conversion Clause: When You Get Married
A well-drafted cohabitation agreement includes a conversion clause — a provision confirming that if the couple later marries, the cohabitation agreement automatically converts into a marriage contract under the Family Law Act.
This is important because a cohabitation agreement, on its own, governs the relationship outside of marriage. If the couple marries without a conversion clause and without entering a new marriage contract, the Family Law Act's default property rules kick in and the cohabitation agreement may no longer govern their financial relationship. With a conversion clause, the same financial arrangements continue seamlessly regardless of whether the couple later formalizes the relationship.
If you already have a cohabitation agreement and you get married, revisit the agreement with a lawyer to confirm whether a conversion clause is present and whether any updates are needed.
Disclosure and Independent Legal Advice
Just like a marriage contract, a cohabitation agreement is a domestic contract under the Family Law Act and is subject to the same procedural requirements for enforceability.
Full Financial Disclosure
Both partners must provide full disclosure of their significant assets, liabilities, and income before the agreement is signed. Courts can set aside a domestic contract if one party concealed material information. Attach a disclosure schedule to the agreement listing each party's assets and debts with approximate values — this protects both of you.
Independent Legal Advice (ILA)
Each partner should have their own lawyer — not the same one — review the agreement before signing and explain what it means and what rights each party is giving up or securing. An ILA certificate signed by each party's lawyer and appended to the agreement is strong evidence that both parties understood what they were agreeing to.
Without ILA, a court has broader grounds to set the agreement aside on the basis that one party did not understand its nature or consequences. The cost of ILA is small compared to the risk of having the agreement unenforceable when it matters most.
When Should You Get a Cohabitation Agreement?
The honest answer: as early as possible in the relationship, and certainly before you make any major financial decisions together — buying a home, combining finances, one partner leaving work to care for children. Waiting until you already own property together or have years of financial entanglement makes the conversation harder and the agreement more complex.
You can enter a cohabitation agreement at any point while you are living together, but earlier is almost always better.
Frequently asked questions
Is a cohabitation agreement the same as a common-law marriage certificate?
No. There is no such thing as a "common-law marriage certificate" in Ontario. Common-law status is determined by how long you have lived together and in what circumstances — not by a registration. A cohabitation agreement is a private contract, not a registration of relationship status.
What if we never get married — does the agreement expire?
No. A cohabitation agreement remains in effect for the duration of the relationship unless the parties agree to change or revoke it, or unless a court sets it aside. It does not have an expiry date. Many couples review and update their agreement when circumstances change significantly (purchasing a new home, having children, a major income change).
Can a cohabitation agreement be changed after we sign it?
Yes. Both parties can agree in writing to amend or replace the agreement at any time. Any amendment should follow the same process — disclosure and ILA — to make it as enforceable as the original.
Does a cohabitation agreement affect child support if we separate?
No. Child support for any children you have together is governed by the Federal Child Support Guidelines and the best interests of the child — the agreement cannot override this. The cohabitation agreement deals with property and spousal support between the partners, not with children's rights.
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