I'm going to refuse to pick my ex up in his car because I need it for my valentine's date
Is there a reason why you will not pick him up?
Because I don't care about him and I'm going to use his car in a reckless way.
It's wrong to use your ex's car in an irresponsible way. You should treat other people's cars with respect because they don't belong to you. I think you should be careful when driving your ex's car.
I don't own it and all you are doing is being paranoid.
Even if you do nothing to the car, it's not yours and you can't use it as you see fit. If you need a car, then borrow it from someone you won't take advantage of.