cahn

Actually my husband is a little like that, although I think he would say he misses me when I'm not around. I'm not sure he would make the distinction between "activity" and "person" in my case? But I've observed that with friendships, and even with his family, although he is mainly an introvert he can be quite friendly to people he likes, and enjoys hanging out with those people -- but he won't make an effort to keep in touch and won't really miss them. (For example, I am always the one who coordinates calling his family because it just won't occur to him that he hasn't talked to his sister -- whom he really likes! -- IN A YEAR.) I have told him that it's a good thing we got married or else we'd probably never talk (we were friends before we started dating), and I would have missed him.

He's not on the spectrum, although he has a BUNCH of engineers on both sides of his family (and is an engineer himself) :)

(He's not like you in many other ways :P :) )