What is a cohabitation agreement and when should Ontario couples get one?

A cohabitation agreement is a written contract between two people who are living together or planning to live together but are not married. In Ontario, it is a type of "domestic contract" recognized under the Family Law Act. The agreement lets the couple define their own rules for property ownership, financial responsibilities, support, and what happens if the relationship ends — rules that would not automatically apply under Ontario law to common-law couples.

The right time to get one is before or shortly after you move in together, when both parties are on equal footing and not yet in a dispute. Courts can set aside agreements that were signed under duress, without proper disclosure of finances, or without independent legal advice. Getting separate legal advice and exchanging full financial disclosure before signing makes the agreement far more likely to hold up.

Common clauses address who owns which property (or what share of jointly purchased property each partner holds), whether either partner can claim support if the relationship ends, and how specific assets like pensions, investments, or a business interest will be treated. A cohabitation agreement automatically converts to a marriage contract if the couple later marries.