how do I tell them?

so, this is gonna sound really weird, but i honestly don't know what to do and I need help.
I have a partner, and they're amazing, and they deserve the world, but I don't think I have any actual romantic feelings for them. I want to break up with them because i don't have feelings for them, but i'm not sure how to. I don't want to hurt them because they're amazing and didn't do anything wrong, I just don't think I can be in a relationship without feelings for the other person.