I don't understand. If it's not erotic, what's the point of corporal punishment? That's not even recommended for children these days, and I'm not sure why it would be considered an appropriate way to resolve conflicts between married partners. If you feel you have done something wrong enough to require "punishment," why not just apologize? Or, if you you both prefer to "punish" each other for wrongdoing, why doesn't he use the same form of punishment for you that you apparently do for him, whatever that is?
I'm not arguing that the relationship is abusive. It is obviously one of mutual consent, at least in your case. So if there's an erotic element, I understand.
You have no obligation to explain it here, of course, but as long as you bring it up, I'm curious.