No matter what, being assaulted is never your fault. It goes against the very definition of it. You didn’t “let” it happen. Your perpetrator knew exactly what he was doing, and knew what you said. No WASN’T an option because he was set on assaulting you. That is what is wrong. He didn’t care about your feelings or respect you. That is a fault of his, and not yours. Confusion is completely normal, but you’re never to blame, and you’re not alone.
I’ve lost count on how many guys have assaulted me. I can’t remember all of the times anymore or all of the guys.