Insurance typically follows the car and not the driver, which means other licensed drivers can use your car. However, and I'm aware this is policy dependent, insurers generally do not allow for repeated use of a car by other drivers, especially if they live in the same household without being added to the policy.
However, imagine a scenario where one is the title holder and allows someone else that has been added to the policy to use a car. However, the person added to the policy lives with someone else and repeatedly allows that person to use the car against your wishes, which means the insurance company could potentially deny coverage.
Can you be held liable if the person (roommate) not on the policy gets in an accident even if the person that is on the policy didn't honor your request (you are the title holder)? In such a situation, should one retake possession of the car in order to avoid liability issues?