Can we sign a cohabitation agreement after we've already been living together for years in Ontario?

Yes. There is no requirement under Ontario's Family Law Act that a cohabitation agreement be signed before the couple moves in together. Couples who have been living together for years can still enter into a valid domestic contract at any point during the relationship.

However, agreements signed later in a relationship face additional scrutiny. Courts will examine whether the agreement fairly reflects each party's current legal position and whether there was any pressure or power imbalance at the time of signing. If the couple is already in conflict or one partner has significantly more financial power, a court may be more willing to look closely at whether there was genuine independent consent.

Full financial disclosure of each party's assets and debts at the date of signing is just as important for a later agreement as for an early one. Both parties should still obtain independent legal advice. The practical benefit of signing later is that the couple's actual asset situation is known — there is less speculation about future property — which can make some clauses easier to draft clearly. A lawyer can advise you on how to structure an agreement that reflects your current situation fairly.