It's been a minute but did that "friendzoning in elementary" thing for Yuzu come up at literally any point before this? I don't remembering seeing that, but I can't say I really care to reread this to find out.
It's not an inaccurate assessment. Sure he doesn't beat her, but he expressly brought her in because he thought her murderous instincts would stimulate the den of wolves he calls a family.