Naruto's reaction would be complex. He would be devastated because his bond with Sasuke is so deep. However, he also trusts Sasuke to an extent. So, he would be torn between his immediate emotional response of anger and his long - standing faith in Sasuke. He might start to look for clues and evidence, and in the process, he could end up uncovering Kabuto's devious plan while also reaffirming his friendship with Sasuke. He would probably be more determined than ever to set things right and prove Sasuke's innocence if he is indeed innocent.
Well, it might show Sasuke being put in compromising situations by Kabuto's schemes. For example, Kabuto could use his medical ninjutsu knowledge to create illusions that mislead Naruto into believing Sasuke is unfaithful. The plot could then revolve around Naruto's reaction and how he tries to uncover the truth.
Naruto would be extremely hurt. He loves Hinata deeply and to find out she cheated with Kiba would be a huge blow to him. He might go into a state of shock and disbelief at first.
Naruto would probably be angry at first. He's always been a free - spirited person, and being kidnapped by Sasuke, his friend - turned - rival, would surely make him mad. He'd likely try to fight back immediately, using his ninja skills and his never - give - up attitude.
There would be other fans who might be intrigued. They like to explore different 'what - if' scenarios in fanfiction. They would see it as a creative way to explore the characters in a new light, even if it goes against the canon. However, they would also be aware that it's just a fictional alternative and not the real Naruto story.
Sasuke could be intrigued. If he comes across a well - written fanfic that really captures the essence of his relationship with Naruto or offers a new perspective on his goals and journey, he might get drawn into it. He might start to think about how these different ideas could fit into his own understanding of his life and the world around him. For instance, if a fanfic shows him a different path he could have taken, it might make him reflect on his choices.
Naruto would be devastated. Sasuke is his closest friend and rival. He would likely go into a state of deep mourning at first. He might isolate himself for a while, just trying to come to terms with the loss.
I'm not sure if there is such a specific fanfic. Fanfiction can cover a wide range of scenarios, but cheating themes might not be very common in the Naruto fanfic world, especially considering the strong bond between Sasuke and Naruto. However, with the vast amount of fanfiction out there, it's possible that one exists.
A third group of fans might simply ignore it. They are so set on the original story and the positive portrayal of Sasuke and Sakura's relationship that they don't want to engage with any fanfic that goes against that. They might consider it a disrespect to the original creators' intentions for the characters.
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.
Naruto himself would likely be outraged. He has his own goals and reasons for his relationship with Sasuke, and being labeled as a 'fan' by Ino would be offensive to his pride. He'd probably try to set the record straight right away.