Thank you so much for reading! I'm happy you liked this one! Infidelity is a favorite theme of mine, though I know it's a difficult topic for a lot of folks. Here, I was thinking that Snape was still a professor at Hogwarts (he gave up his headmaster position to Minerva) and the shopkeeper knows it, so calls him Professor. :) It's interesting that you felt Harry suspected or knew something was going on--my own view is that he didn't know, though I think there's plenty of room for a different interpretation! Thanks again for reading and your lovely comments!