Responses
I 100% get where you're coming from, but a lot of demons hate humans because they betrayed them. She is the demon Lord so she has to be an example for everyone else. Her popularity would greatly diminish if she got a human lover
Wouldn't it be easier for her to just let the rumor that she has a human "pet"/lover run? It would make him able to be around the castle, maybe even be trained next to her soldiers instead of her having to train him herself