Lol sadistic? Learn vocabulary before you try to use it. She is probably a masochist. They enjoy pain. But this is also a dominance act.

The sex has been wonderful, but she has a thing about wanting me to spank her. At first I laughed, as I thought it was quite an odd request. But it was clear she was serious, and this is where the problem lies. I have spanked her a few times and, though it arouses her, it makes me feel guilty.

When I started dating my wife it was like most relationships. The sex was new, fun and frequent. Over the first few months nothing out of the ordinary happened. One night while we were fucking she blurted out for me to tell her she was a "bad girl" and needed to be punished. Without thinking I told her that she was a bad girl, and then just blurted out that she was my slut and that I was going to use her anyway I wanted.