It helps to hear another perspective. I often think I'm creating the problem by over-thinking why he might do, but in this case, I think there is no way I can give him access to the car. In any case, it's unregistered, has a flat battery by now and is only drivable in first gear/reverse.
Thanks for your thoughts about the yacht stuff. Makes me so mad, it's good to know someone is on my side.
I don't think I could ever trust him again, but who knows. I've thought a lot of things in the past that don't hold now. I don't even look at the possibility of a future with him at the moment, though.