Mr Smith:
It is apparently a fairly common phenomenon.
i don't know if i would call it "sympathy," but my initial weight gain started when i was dating a very fat woman. i was only 160 lbs when we met, but just i kind of fell into her lifestyle. we went out to eat and drink a lot, and that really rubbed off on me. i started to really enjoy food more than i had in the past, and that was when i first gained a fat belly.