I’m not even sure it is about the deception. Deception is not always wrong, not even deceiving those we love: there’s surprise parties, gifts bought well in advance, whole arrangements surrounding proposals, all of which include deception. But that’s different. Why is it different? Because of what it communicates. How the person deceiving you sees you. The good kind of deception obviously communicates “you are special to me”. The bad kind of deception communicates “I think you are dumb/boring/too fragile to handle the truth” That’s the part that hurts.