Frank Thewes is used to hearing from people who wake up on the wrong side of bed because of their partner’s sleeping habits—but who don’t want to move into separate rooms. He was one of them, once.

DEAR ABBY: I moved away from my hometown 10 years ago, and I have a dear friend of nearly 30 years who still likes to sleep next to me when she visits. This is becoming so annoying that I don’t want ...