One of the fun things about dating someone you've known for twelve years is that you have lots of memories of each other. Most recent memories:
When I was in M's freshman class, I recall, early in the class, him making some remark about an old song--and how it was about giving (or getting) a blowjob. I was 18 and impressed. "So this is college, eh? Sexy professors talking about blowjobs in class? Clearly I'm on the right path in life."
I shared this memory with M, and he swears he would never talk about blowjobs in class. Unless it was something in a novel, in which case he might talk about it, just to, you know, bring it to the students' attention. Anyway, he denies that he talked about blowjobs when I was in his class. Clearly, he's a liar.
The most recently revealed memory: M told me last night that, eight years ago, he may have masturbated while thinking about me. And it may have been to some image of me wearing a very sheer blouse. And this might have occurred during the time period when he was supervising me.
All possibilities. All probably true.