How does a spouse who isn't on title protect their right to stay in the matrimonial home in Ontario?

A spouse's right to possession of the matrimonial home under Ontario's Family Law Act exists automatically by law once the couple is married and the property is ordinarily occupied as their family residence — it doesn't depend on registering anything against title, and a spouse who isn't an owner already has this protection without taking any extra registration step. This is different from an ownership interest, which the non-titled spouse doesn't gain just from this right.

Where practical concerns arise is around third parties, like a buyer or lender, who might not otherwise know a property is someone's matrimonial home. This is generally addressed on the other side of the transaction, since the titled spouse or their lawyer is typically required to provide a statutory declaration confirming marital status and matrimonial home status before a sale or mortgage can proceed. A non-titled spouse who is worried their partner might try to sell or refinance without their knowledge, particularly during a separation, should raise this directly with a family lawyer, since there may be additional protective steps available depending on the circumstances, such as addressing the issue in a separation agreement or, where there's an active dispute, seeking a specific court order.