He could be angry. Naruto has a temper, and being cheated on by Sasuke would likely make him furious. He might even want revenge.
Naruto might be heartbroken. He's a very emotional character, so he could cry a lot and feel a deep sense of loss.
He might also become more reserved in future relationships. After being cheated on by Anko, Naruto could be more cautious when it comes to getting close to someone again, always having that fear in the back of his mind that he could be betrayed once more.
Naruto could also be deeply hurt and go into a state of self - reflection. He might question his own judgment in relationships. For example, he could think about what he did wrong or if there were signs he missed. This could cause him to leave to find himself and grow stronger on his own. He may start to focus more on his ninja training and his friends in the village, trying to move on from the pain of being cheated on.
One common reaction could be Naruto's shock. In most fanfictions, Naruto is portrayed as someone who deeply loves Hinata, so being cheated on would leave him completely stunned.
Some fans might be outraged. Naruto is a beloved character, and the idea of him being cheated on by Boruto goes against the positive father - son relationship they expect. They would see it as a distortion of the characters' true natures.
Fans would likely be divided. Some fans who like exploring unconventional and darker storylines might be interested in such a fanfic. They might see it as a creative exploration of the characters. However, many fans who are loyal to the original relationships in the Naruto series would probably be outraged. They would feel that it goes against the essence of the characters and the positive relationships that were built up over the course of the series.
There would be a lot of shock and disappointment among fans. Naruto and Hinata are a beloved couple, and fans who have followed their story would find it hard to accept such a plot. Many would probably criticize the author for going against the essence of the characters.
If Naruto gets cheated on by Sasuke in a fanfiction, it could greatly disrupt the traditional bond between them. It might lead to Naruto feeling betrayed and could potentially make him more cynical. This could change the direction of the story, perhaps leading Naruto to focus more on his own self - growth rather than their relationship.
Well, one possibility could be that Naruto discovers that his friends have been secretly working against him in some way, like lying about their intentions or using him for their own gains. Maybe they've been making deals behind his back that go against what he believes in.
One possible plotline could be Naruto's initial shock and disbelief. He might go through a period of self - doubt, wondering what he did wrong. Another could be his journey to find himself again after such a betrayal. He might focus on his ninja training more intensely to distract himself from the pain.
One possible scenario could be a power imbalance. Maybe Sasuke discovers some new, extremely powerful jutsu that Naruto has no defense against. For example, a jutsu that can nullify Naruto's chakra or attack his spirit directly. Another possibility is a miscommunication or a breakdown in their relationship. If Sasuke believes Naruto has betrayed him in some way, his anger could lead him to kill Naruto. However, this goes against the core of their bond in the original series.