I vote for insecure, but could also be ex has told her some crazy BS about you.
How about turning up at the door looking like you're ready for a fashion shoot, and swatting ex on the butt as he turns to leave - just to get her goat? (Ok, not really, and thank god she's not coming to the door, that would be too creepy. And I'd have trouble not spitting in her face. Then again, she's won the "prize" of a super creepy guy who you are better off rid of, so I kinda feel sorry for her. So maybe I'd just give her the stinkeye instead of spitting on her. But that's just me )