
His fault is giving his *sister* the household authority that belonged to his *wife*. His sister would have her own authority once she herself got married and moved away, moreover since they all knew she'd be getting married to the effing Crown prince, no less! (or at least, that's how they all knew it was going to be, before Terrence appeared). Thus, giving his sister authority over his own wife was definitely overkill, NOT needed, and a serious offense to his wife.

I know, but that IS actually the point of ch41: that's why the FL calls him out on trying to use the "I didn't want to get your hopes up" excuse for the way he treated her, when the truth of the matter is not that he was unable to reciprocate love, but the way he disrespected her AS A PERSON: not being willing to have sex with her didn't mean he also had to ignore her whenever she talked to him, or side with his sister whenever the sister wanted to walk all over her. Those are two separate things. As she pointed out, during their marriage he always trampled on her dignity which was basically a form of punishing her for HIS own mistake of confusing the familial love he felt for her with romantic love, because he was too proud to admit he had been the one make a mistake.

To sum up: that being asexual doesn't give you the green card to treat people bad... not even in order to "not get their hopes up". He should've been honest with her about his "problem", and agreed that while he wouldn't ever touch her, he'd still acknowlege her and treat her with due respect OUTSIDE of the bedroom
Ok so yes hes a terrible husband yadda yadda. But i feel like he could have been asexual. He still experienced romantic love but no sexual attraction.