My head is all twisted

So, there's this guy. Yeah. My ex, who I haven't seen in 6 or 7 years. I can't figure it out exactly because I'm afraid it's been much longer, which makes me feel really old. But I met him over 20 years ago, so there's no question that we are old. We could be grandparents together. Instead, we're just - what?

Of course the story is more complicated - after our own relationship fizzled, we kept in touch, and went through periods of time where we were what the kids now call "fuck-buddies." Meaning that we had sex without dating, or the pretense of dating, or the promise of dating. Sometimes even when dating other people - though to be fair, on the rare occasions I was involved with someone else, I never saw him. I can't say the same for him, which some might view as much a moral lapse on my part, but I always saw it as I was a free woman, he was the one fucking around on someone he'd made promises to. This went on for over a decade. Fifteen years? Twelve? Ah, again with the time. Let's just say it petered out as time went on, and then we came to this long span of time without seeing one another.

So he's in town, and wants to see me, and so we meet for dinner. And part of me thinks this is a perfect opportunity for great sex, and part of me thinks I should just say no, and part of me is just curious to see him. Part of me is excited by the prospect, but I don't think it's healthy. On the way, I decide that I'll rebuff any advances, because who really needs to get all twisted in that again, even if the sex is still good? He's married now. If he doesn't respect that, I should. Right?

Dinner is okay, pleasant, chatty, and it ends, and nothing happens, and I walk away feeling both relieved and a bit disappointed. Is that normal?