@slime_sleeper In my opinion from what we know so far, I don't think Doubayashi is
completely at fault or an asshole. From the book and souvenir chapters Nao seems like she can be really demeaning.
I could easily see a situation in their relationship where he's overworking himself to the point of being seemingly uncaring in the relationship because he just wants her to acknowledge how hard he works.
But instead all she
seems to do is criticize him and cut him down, so it starts this feedback loop of >Get Criticized>Work Harder>Repeat