How does a cohabitation agreement protect property I owned before moving in together?

For common-law couples in Ontario, each partner already keeps their own separately owned property when the relationship ends, because common-law partners have no statutory right to equalization. But complications arise over time: separate property can become commingled with joint finances, improvements can be made to one partner's property using shared money, or one partner may contribute to the other's mortgage — all of which can give rise to trust-based claims.

A cohabitation agreement can prevent these complications by clearly stating that property owned by each partner before cohabitation remains that partner's sole property, including any increase in its value. It can specify that contributions to one partner's separately held property (such as paying down a mortgage) are treated as gifts or as loans to be repaid, rather than as generating an ownership interest.

The more specific and detailed the agreement, the more useful it will be if the relationship ends. Attaching a schedule listing each partner's significant pre-relationship assets at the date of signing creates a clear baseline. This is particularly valuable for partners who own real estate, a business, an investment portfolio, or other significant assets before moving in together.