Finally a moment where I can prove somebody wrong! Two years ago when I was a college junior I was in a very small writing class that was super informal, and the professor was only in his mid-thirties. I was openly flirty with him, and we were both single, and even though we both knew it wasn't the best idea, halfway through the class we started hooking up like five times a week, a couple times even in his office on campus. We kept seeing each other over the summer, but it eventually fizzled out. Not sure if this counts as an "affair" since he wasn't married, but I look back at it fondly, I pursued him mostly so it wasn't him using his power imbalance, and it was some of the best sex I ever had, and I had a fun time exploring roleplaying by playing up the teacher/student dynamic during our sexy times.