What happens to our cohabitation agreement when we get married in Ontario?

Under Ontario's Family Law Act, a cohabitation agreement that was made while the parties were living together automatically becomes a marriage contract if the parties subsequently marry. No additional signing or formality is required for this conversion to take effect.

However, automatic conversion does not mean the agreement is necessarily well-suited to the new marital context. A cohabitation agreement is drafted with common-law partners in mind, and the legal framework that applies to married couples differs in important ways. Married spouses, for example, have equalization rights in property and the special matrimonial home rules that do not apply to common-law partners. A cohabitation agreement that was appropriate for an unmarried couple may not address these issues in the way either party would have intended.

The practical recommendation is to review the agreement with your respective lawyers around the time of marriage — or shortly after — to ensure the clauses still achieve what you intend now that the legal context has changed. You may want to sign a new marriage contract that is drafted specifically for married spouses, superseding the older cohabitation agreement. This is especially important if the couple owns a home, has acquired significant assets since the original agreement was signed, or if the original agreement was drafted before either party had legal advice.