Not RTFT.
I'm quite pragmatic in these situations.
Attraction happens. It's a reminder that you're both human. You don't need to act on it in anyway.
Sometimes, when there is chemistry there, it's not a conscious thing you are doing that other people pick up on.
I've been with someone for coming up to a year. He was with someone else when we first met a few years ago. Apparently, he had a huge crush on me and, as time went on, fell in love with me. I had no idea. I thought he'd barely noticed me because he kept away from me. When we got together, all our mutual friends said they knew I'd been in love with him too because they could sense it.
It was news to me - unavailable men aren't even on my radar and, until they split up, I'd never even thought about whether I was attracted to him or not. But, on reflection, they were right. 'Chemistry' is sometimes just there.
But that's all it is. You have no idea if you'd be compatible together, no idea what he's like 'behind closed doors', no idea what a relationship would look like. Just remind yourself of these things and continue to avoid him as much as possible.