At the end of the day just like you said insurance won’t allow that anyway. And if you do drive anything you do in the car accident our ticket her insurance will rise. And now with DC new law you get points on your license for camera tickets (which will go on hers) next year. Getting a car is your easiest and safest bet. Our just deal with whatever repercussions you have bye using your ex car! Sounds like you already have your answer as well! You gotta use her car lol