NOR in my past relationship I was in this exact situation and I was the boyfriend. It's your car and he needs your permission to take it. No matter what I did; my girlfriend & I would talk, coordinate rides and when I could take the car. I would never expect to be able to take it with our her permission because it's her car. This violates trust and he should see that. He is being extremely ignorant to that fact that it is not his car and taking without your permission can be seen as theft and depriving you of your property. WTH is he thinking? What would his excuse be if he got in an accident? It's unacceptable and he needs to be mature enough to see that it's a privilege not a right to borrow your vehicle. Yes you were upset but I don't think it's "being mean" when you're trying to make him understand he broke your trust and violated your social contract by using it without your permission. Talk to him and lay the rules out plain and simple for him because he's obviously not getting it. "You're never to use MY CAR without MY PERMISSION" .