Unexpected dirty offer

I just had the weirdest evening. I went to the reunion. And it was fun and calming to be amongst like-minded people, sharing stories and feelings and laughs. And I was happy. Then orgsniser guy shows up. And there's happy and squee and good news and tears and trailers and talk about next weekend. And he talks me and the friend I came with into going to this party further up in the building. We had a flirty exchange on a joke I had made online earlier, and I was laughing my ass off and giving it my most aggressive cause, well, fun!
Then we go to the party floor, and I dance and have a drink and talk, and organiser guy gets me a drink. And asks if he can be really forward and inappropriate with me. Which I didn't object to. So he says it's of course just fine if I say no, but he's been interested since he first saw me a month ago, and finds me really attractive. I of course blush and thank him, and he continues, repeating that he'll respect a no, bit how would I like to find a dark private place and just fuck, cause he's really into me. And my jaw dropped, mentally. I told him that's really not my thing, but damn, points for being direct, cause it makes it so much easier to know what the fuck is going on. I tell him I just got out of a long and complicated relationship (to which he said he knew, how the f did he know?!) and I feel too screwed up to really involve myself in any way with anyone. He then tells me he's married, but in an open marriage, so it wouldn't be leading to anything, if that's what I was worried about, but he fully understood. I told him to ask again in a few months when I got my shit sorted out. It was very.. Direct, no shit, and adults talking about an informed decision. And that totally had my hormones reacting. What the fuck. I only danced with him after that, and okay, yes, I did do sexy moves, and he almost kissed me, but my good sense kicked in then, and I turned away, pushing him off. And he just smiled, hugged me and thanked me for the dance.

It was... Fucking weird, but very flattering. My head is having trouble understanding where it came from. I should have a warning sign on my forehead. But apparently that makes me attractive?

WTF.