Well, some authors might write it to show the fallibility of the characters. Even though Sasuke and Naruto are strong in the original story, making fem Sasuke cheat could be a way to humanize her more. Also, it could be a way to introduce new plot elements and new characters that come into play because of this situation. It's all about creating a different narrative within the fanfiction world.
Perhaps the author is trying to break the mold of the traditional Sasuke - Naruto relationship. They want to add a shock factor and make readers think about relationships in a new way. It could also be a way to explore the consequences of actions that go against loyalty and friendship. In fanfiction, the sky's the limit when it comes to reimagining relationships, and this is just one extreme way of doing it.
One reason could be the author's desire to create drama. By having such a betrayal, it amps up the emotional turmoil. Another could be to explore different relationship dynamics. Maybe the author wants to see how Naruto would react to such a situation, which is a way of testing the limits of their bond.
One possible reason could be jealousy. Maybe fem Sasuke is jealous of Naruto's natural charisma or his ability to make friends easily. Another reason might be related to their different goals. If fem Sasuke has a very different view of how to save or change the ninja world compared to Naruto, it could lead to hatred.
One reason could be to create a lot of angst. If Sasuke cheats, it would deeply hurt Naruto and cause a rift in their relationship, which could lead to a lot of emotional turmoil for both characters. This would make for a very dramatic story.
Well, Naruto has always been there for Sasuke in the original story. In fanfiction, Fem Sasuke might secretly like Naruto because she sees his loyalty. He's constantly trying to bring Sasuke back to the right path. This loyalty could translate into a deeper affection in the fan - created stories.
Some fanfic authors might write it as a form of wish - fulfillment. They might prefer the Naruto - Sakura relationship more than the Sasuke - Sakura one. So, they create a scenario where Sakura turns to Naruto in a romantic way. Additionally, it could be a way to explore the characters' personalities further. For example, how Sasuke would handle being betrayed and how Naruto would deal with being involved in such a situation. It gives a chance to dig deeper into their emotional and moral aspects.
It could also be a way for the writer to express their own dissatisfaction with the original relationship between Sakura and Sasuke. Maybe they felt that Sakura's character was not well - developed in the context of that relationship and decided to create a more 'dramatic' storyline through cheating.
One reason could be to create drama. The idea of a relationship being broken by cheating is full of emotional turmoil which can make for an interesting read. Another reason might be some writers' preference for the Sasuke - Karin dynamic. They might see potential in their relationship that wasn't explored in the original series.
Well, there might be such fanfictions out there, but I don't really recommend them. Cheating in any relationship, even in fan - made stories, can be a bit hard to stomach. And in the Naruto universe, Sasuke and Naruto have such a deep bond that this kind of plot goes against the essence of their relationship.
Maybe to explore different character arcs. The writer might want to see how Sakura would develop as a character if she strayed from her loyalty to Sasuke. It could also be a way to introduce new characters or relationships into the Naruto fanfic world.
One reason could be to create drama. The Naruto series has a large and passionate fan base, and a plot like this would shock readers and generate a lot of discussion. Another reason might be that the writer wants to explore different aspects of the characters. Maybe they think Sasuke has a side that could be tempted to cheat, or they want to see how Sakura would handle such a situation.
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.