If your common-law husband is driving your car, with your permission, he will likely be covered by your insurance company. But since he does live in your household you should inform your insurance agent of him driving your car because their underwriting rules might require him to be added to the policy for full coverages to in force when he is driving your vehicle.
Remember, in Ontario as the owner of the vehicle, you are responsible for anyone who drives your vehicle with your permission. If your husband has an at-fault accident while driving the vehicle, the accident could become part of your driving record and affect your insurance premium since both the vehicle and insurance policy are in your name.
You can go here for a Canadian car insurance rate quote for you or your common-law husband.