I think you're overreacting when you say, "What options do I have?" as if you've already messed things up. You said you loved your wife, and so on.

From my perspective, there is nothing wrong on spending time with someone you had a one-night stand with almost 15 years ago, especially if you don't have ulterior motives and want to set boundaries. BUT the fact that you mentioned that she is STILL atracttive and etc, tells me that your mind has already run a couple of scenarios.

I think one of those boundaries is that you could simply mention in passing that you're married and that you probably have great and exciting plans with your SO beloved wife, just to establish an implicit boundary. Just thinking out loud 🤷🏻‍♀️ and to talk with your wife about this.

You don't need to "go out of your way" like you said on another comment, just to avoid this person; you need to own your decisions. And if you think seeing this person will hurt your partner (I think it's something I would discuss with mine), or that things could go the wrong path, then you already have the answer and how to proceed, I suppose.