One idea could be that Hinata is forced into a situation where she has to pretend to cheat on Naruto for his own safety. For example, a powerful enemy wants to target Naruto through Hinata, so she fakes an affair with another character to make Naruto seem less important to her in the enemy's eyes.
Another could be a misunderstanding - Hinata is seen in compromising situations that look like she's cheating, but in reality, she's just helping a friend in secret. Maybe she's helping a character who is being hunted and needs to hide their relationship from Naruto for the time being, which causes false rumors of cheating.
Well, first of all, don't make it about actual infidelity in a malicious way. Instead, focus on misunderstandings. For example, Hinata could be misunderstood as cheating because she's spending a lot of time with a character who is teaching her a new jutsu (ninja technique). People misinterpret her intentions, and Naruto also gets the wrong idea at first.
The theme of family also appears often. As they start their own family, fanfics may focus on how they raise their children, pass on their values, and how their family interacts with the rest of the Hidden Leaf Village. There are fanfics that show Naruto and Hinata teaching their kids about the importance of hard work, friendship, and loyalty, just as they learned in their own lives.
One interesting plot could be a story where Naruto Hyuga (assuming it's a new character related to the Hyuga clan) and Hinata Uzumaki (again, a new take on Hinata) team up for a secret mission in a far - off land. They could face challenges like ancient curses and powerful, unknown enemies. Along the way, they discover new jutsu and also explore their feelings for each other in a more in - depth way.
One common theme could be miscommunication. Maybe there's a misunderstanding that leads Hinata to be in a situation that looks like she's cheating. Another theme could be exploring different relationship dynamics. It might show how Naruto and Hinata's relationship is not as perfect as it seems and how they deal with issues. But overall, these are quite rare compared to the more positive portrayals of their relationship in the Naruto world.
One common theme could be miscommunication. As I mentioned before, Naruto might be in a situation that Hinata misinterprets as cheating. Another theme could be trust issues. The story could revolve around how their relationship is tested due to the false belief of cheating and how they rebuild trust.
One idea could be a comical story where a Hyuga character accidentally uses their Byakugan on a cow and discovers some strange chakra patterns within it. Maybe the cow has some secret connection to an ancient Naruto - related power.
There might be some fanfics out there with such a plot, but it's not a positive or common representation of the Naruto characters. In the Naruto series, Hinata has always admired Naruto from afar and they end up together. Sasuke has his own story arc that is mainly focused on his revenge and redemption. Changing their relationships in such a way in a fanfic seems like a distortion of the original story's essence.
I'm not sure if there is such a fanfic. Cheating storylines in fanfics can be quite controversial as they go against the positive relationship often depicted between Naruto and Hinata in the original work.
Some fanfics focus on the idea of alternate universes. For example, what if Naruto had noticed Hinata's feelings earlier? Or what if Hinata was the one to save Naruto from a difficult situation instead of the other way around? These alternate scenarios allow for different takes on their relationship and add an interesting twist to the traditional Hinata x Naruto story.
One great 'Naruto and Hinata Hyuga' fanfic is 'The Bond of Two Hearts'. It beautifully explores their relationship post - Naruto's journey as Hokage. It shows how Hinata supports Naruto in his new role and how they grow together as a couple.