Hiding My Kink from My Partner

I've been in a committed relationship with my partner, Alex, for two years now. We have an amazing connection and we enjoy each other's company deeply. But there’s something I’ve never shared with him, and it keeps gnawing at me every day. Lately, I’ve been really turned on by the idea of having sex in a public place, somewhere where anyone could walk in and find us. I imagine being tied up, exposed to the world as I cum hard while someone else fucks me rough. It’s this intense fantasy that feels so wrong yet exhilarating at the same time. I’ve never acted on it, I know how dangerous that would be, but I can’t help but wonder if there’s something seriously wrong with me for even thinking about such a thing. My partner and I have talked about our sex lives openly before, but this just feels too taboo to bring up. Am I the only one who feels this way? Is it normal to want public places where anyone could find us? It makes me so horny that I can barely think straight sometimes. I need some kind of validation here, am I an awful person for these thoughts, or is there a chance this is just another kink that’s out there but no one ever talks about openly? Can you share your experiences with public sex fantasies and if it’s common in relationships?