Maybe next time he visits, if he's still trying to make sure you aren't going to get the wrong idea - you could arrange to have to leave in the evening for a date! I'd love to see the look on his face when you get all dolled up to go out and leave him there for the evening with D! Even better if you come home very late and slightly drunk!
Obviously, this is only useful if he's still trying to assert that he's your exH - if he really seems to be testing to see if you'll be nice to him, I'd hold off.
I'd love to see the look on his face when you get all dolled up to go out and leave him there for the evening with D! Even better if you come home very late and slightly drunk! 
