There are some people pretty close to being pure on both sides of the morality scale. And his wife has got some kink to her, which is always a nice surprise.
@Despada That seems like a good subject for the exploration of politics if they wanted to go further into it. I mean marrying is already a big deal but in many settings humans in the demon lords castle would be distasteful. The extreme might even lose faith having only thought of the wife as a plaything until now.
Again, clearly a lot of racism going on in this story's background. So they could explain it or have an arc around it.