
Being asexual myself I don’t really find this weird or unrealistic because this kind of people exists. However I agree that a lot of authors tend to avoid having a mother or a stepmother, I think it’s because they want to focus on the relationship between the male and the child or they would make an unrealistic woman. Idk for me it would be unrealistic, even if it happens in a lot of stories, that the mother would accept immediately and love unconditionally a child they didn’t even choose to bring to their home. And if they don’t do that they tend to make an horrible mother who will never accept them and an abusive circle takes place which I think is not great for a fluffy, light story. It takes a lot of effort to place this figure so I think they don’t want to deal with it.
However I’m still not sure if he really is her father or her brother in the story, it would make more sense if he is the brother to me.
Sorry I talked too much and sorry for my poor English ┗( T﹏T )┛

You are right on this one. I do think it should be possible to write just a loving mother or stepmother as well, right? Or even better yet, if they don't need another female lead but the daughter, the father can still have an active adult life. It's just that this is like the 10th manga I have read on such relationships where the men are portrayed as celibates and have no existing sex life.

No, your English is perfect. I had definitely thought about the asexual part of it. It definitely makes sense if the males (fathers or brothers) are asexual.
I do think it had more to do with your second point. Introducing a mother or step mom will destroy the father/daughter alone fantasy that the story communicates. I was just thinking that the it should be possible to have a sex life but still cherish your daughter to death. Sometimes the authors write it as a mutually exclusive situation. It gives me similar vibes to when they vilify all women in the story apart from the female leads and make the men heroes. Isekai is packed with internalized misogyny.
I honestly think he is the brother, not the father.
Okay on the side note, I don't know why I am obsessing over the sex lives of ML when in many shonen, the characters also have none. I think it is also something to do with the audience. If it targets younger people, there is no need to pursue the sex life. Sorry for the long essay,

Don’t worry! I agree we notice it more in this genre, maybe it’s because it’s more focused on everyday life and since it includes a daughter or a son we might tend to think about it while shonen focuses more on the actions maybe ^^
I also like when the side characters or villains are realistic or relatable. Even if it’s good to have a character rotten to the core, it’s not when it’s all of them. Authors tend to vilify all the other women to make the fl more angelic and loves I think but it’s not interesting :/
And thank you for the compliment :3
Ok y'all don't kill me on this one. I am thinking out loud. So anyway, I am an isekai lover. I have noticed in many father/daughter loving relationships, they tend to portray the men, older adults over 25 years as this celibate men who have no sexual desires. I am not saying every male out there has an active sex life, just that it tends to look like the authors can't balance two women in the lives of their protagonist.
Look, they don't even need to be married. But the complete lack of a sex life for an over 25 male is a bit unrealistic. Obviously these are fantasies and they can write whatever they want. Anyway, it was just an interesting observation. Sometimes it is written as if loving a daughter can compensate for romantic love. It can sometimes though.
Ok, at this point I have lost my original thought. Do ignore me please.