white flower wrote:Why is he attracted to and avoidant towards me?
Your romantic interest in him is going to provide him with massive supply, probably more supply than he'd get in other situations. Plus, he may be an NPD, but he's still a man, and is going to desire the company of a woman and the physical intimacy that your attention makes possible. At the same time, just as you ascertained, he is likely experiencing engulfment/attachment fears and his defenses are triggered by the emotional intimacy between the two of you. If you put all of that together, you end up with the very type of behavior that you described, where he is both attracted to you and avoidant of you.
I think for a lot of NPDs, romantic endeavors are kind of like a very potent drug. The drug provides them with a greater high than would other drugs (other forms of supply). But coming down from the high sucks and the drug has numerous unpleasant side-effects (anxiety, etc). So the NPD is stuck trying to decide whether he wants the high from the drug, or whether he'd rather pass up that high and avoid dealing with the side-effects. Hence attraction-avoidance.