Does a cohabitation agreement expire in Ontario or does it last forever?

A cohabitation agreement in Ontario does not have an automatic expiry date — it remains in effect indefinitely unless it is revoked or superseded. This is true even if many years pass between signing and the end of the relationship. Courts have enforced domestic contracts signed decades earlier, provided the formal requirements were met and no grounds for setting aside the agreement exist.

However, the age of an agreement can become a factor if circumstances have changed so dramatically that enforcing it would produce a very unfair result. Courts have discretion to look at whether significant unanticipated changes — such as a long illness, a dramatic shift in financial position, or children — make enforcement unconscionable. This is not a guarantee of revisiting old agreements, but it is a recognized risk.

The practical recommendation is to review your agreement periodically — particularly when major life events occur (buying property, having children, receiving an inheritance, a significant change in either partner's income or career). Many lawyers suggest a review every five years as a matter of routine. If the agreement no longer reflects the couple's actual situation and intentions, it can be amended or replaced with a new document through the same process as the original.