Well, it could be that the writer wants to explore different character traits. Maybe they want to see how Naruto would react in a situation that goes against his moral code, or how Hinata would handle such a betrayal. It's a form of character study through a very controversial and unorthodox plot. However, this doesn't mean it's a positive or well - received concept in general.
It could also be a way for some fans to explore alternative relationship dynamics. Maybe they were not fully satisfied with how the relationships in the original Naruto story developed. For example, they might have always thought there was some unspoken tension between Naruto and Sakura that could have led to something more, and this is their way of exploring that idea in a fictional and extreme way. However, this does not justify the unfaithful nature of the plot.
One reason could be for the sake of creating drama. Fanfic writers often like to explore extreme scenarios that deviate from the original story to generate intense emotions and reactions from readers.
Well, one reason could be that some fans are just exploring alternative storylines out of boredom. They might think it's interesting to see what would happen if they break the established relationships in the Naruto world. Another reason could be that they are trying to add more drama to the story. However, these fanfics don't represent the true nature of the Naruto characters as they are in the official series.
One reason could be for the sake of creating drama. Writers might want to explore how the Naruto universe would be shaken up by such an event. It could also be a way to explore different character aspects of Naruto and Hinata that aren't shown in the original, like how Naruto would react to such betrayal.
One possible reason could be a misunderstanding. Maybe Naruto was in a situation where it looked like he was cheating, but in reality, it was all a big mix - up. Another reason could be that the writer of the fanfiction wants to explore a darker side of Naruto's character. Or perhaps there's some sort of outside influence, like an enemy using some kind of mind - control on Naruto to make him act out of character.
Some people might write it because they prefer other characters over Naruto, Hinata, and Sakura. They could be trying to promote their favorite characters by putting these three down in their fanfiction.
One reason is that the characters' personalities don't really lend themselves to such a plot. Hinata is deeply in love with Naruto and has been for a long time. Naruto also has strong feelings for Hinata. Their relationship is based on mutual respect and admiration.
It could be due to miscommunication. Suppose there was a misunderstanding between her and Naruto. For example, Naruto might have said something that Hinata misinterpreted as him losing interest in their relationship. This confusion could have led her to seek comfort in another person, which unfortunately led to cheating.
Well, some writers might be interested in exploring the 'what if' scenarios that are not part of the original story. It could also be a way to express their own views on relationships that are different from what was presented in the 'Harry Potter' series. Additionally, it could be a means to add a sense of realism, as in real life, relationships can face such challenges, even if it's not what we expect for these beloved characters.
Some people might create such concepts out of a desire for shock value. They want to create something that stands out, even if it's inappropriate.