A Secret Suffering from Pleasure

I'm in a serious relationship with my girlfriend of three years. Everything seems fine on the surface, and we both try to maintain an open dialogue. But there's this thing I've been hiding, I have a kink for domination that she doesn't know about. It's not just vanilla sex anymore; sometimes, secretly, I fantasize about being taken forcefully in a way that pushes me out of my comfort zone. Once or twice, when we were alone and I had the nerve to hint at something different, her reaction was cold and dismissive. She said she wants us to be normal and respectful with each other. This has left me feeling trapped between what I am supposed to want and what I secretly crave. It's been a heavy burden on our relationship, one that I fear might change everything if it ever comes out.