When in Korea, must we always do as the Koreans do? "When in Rome..."?

Turning your head slowly when you look at a person isn't a known Korean etiquette. When i was reading your experience, I couldn't help but be confused, and I'm Korean myself. I don't think your boyfriend is trying to enfore a Korean etiquette on you, he was simply requesting you to watch something that he personally finds uncomfortable. "When in Rome, do as the Romans do" yes, you should follow the basic cultural ettiquettes in Korea, but don't force yourself to do anything you're horribly uncomfortable with. You aren't supposed to eat before your elders do in Korea, and I got scolded many times in Korea for doing so. This isn't really a very difficult ettiquette to follow so I did as I was told, but speaking in honorifics to a guy that was a year older than me I did not do. I respectively called him oppa, but he was just too obsessed with the seniority system in Korea which was a turn off to me.