Sometimes I Fantasize About Strangers in Public

So there's this thing that's been gnawing at me for a while now. It started last year when we moved to the city and all these new things were opening up around us, like coffee shops and libraries that I'd never seen before. I work from home mostly, but lately, every time I'm in public spaces, like a crowded subway or even just a busy grocery store, I keep catching myself thinking about my partner as one of those strangers. It's strange because we're pretty open-minded at home. We do all sorts of things that I thought would satisfy these urges, but there's something about imagining her among the throngs, completely oblivious to who she is to me, that makes it feel more intimate somehow. Like this private space between us gets expanded into the world. And then I start thinking about how people have no idea what goes on behind closed doors and suddenly, I'm at this coffee shop with a giant window facing out onto the street. I watch as cars zoom by and wonder if anyone else has ever thought something like this. Maybe I should just tell her one day when we're both feeling playful, what if she wanted to dress up and go somewhere crowded together? But that seems so different from my fantasies. I'm not sure what's really going on here, or why it matters so much, but it keeps coming back to me. Maybe this is just some kind of kink I didn't know about until now?