Maybe you should just really bore him to death. And I mean... really bore him. Read up on the most boring topic you can think of, and talk about it obsessively to him for a week, getting upset if he won't listen or doesn't find it interesting. That would probably put him off a bit.
That is delightfully evil. I like it.
Of course he's an Aspie, so she has to make sure she doesn't hit on one of his obsessions, or he'll really fall for the poor girl!