I mean a guy lacking feelings for someone wouldn't exactly drink a person's injury blood the way the King did on a whim, but hey, he probably doesn't even realize it himself yet. And it's a fantasy European setting, and Nina's fifteen and trying to avoid this stuff, the story's already thrown around implications that were she less fortunate she probably would've been sold off to far less pleasant conditions. The big problem is because she looks younger than fifteen (yet Alex had a super huge ass growth spurt after his initial appearances, almost like the artist is adjusting and improving their own designs as they go), everyone thinks the story's dipping into lolicon, but the bath scenes would've been a hell of a lot more awkward if that was the aim.
I'd assume there will be a timeskip if/when the king does take a romantic interest in her, but if not, it's not unexpected for the setting and the artist is fairly clean all things considered. Which is ironic given the contents of the novel Lee drew herself towards in the first place.