Dear Prudence,
My next-door neighbor has been having an affair for the last few months. He works from home, and nearly every day, a woman shows up about 30 minutes after his wife leaves for her commute. I know they are screwing because I have a clear view of their bedroom window from mine upstairs, and they don’t bother to pull the shades down. Am I under any obligation to inform his wife of what’s been going on under her nose? My husband says we need to stay out of it.