One possible reason could be a misunderstanding. Maybe Harry was wrongly accused of something, and Ginny's temper got the better of her. For example, if there were false rumors about Harry being unfaithful in the fanfiction world.
Perhaps there was some kind of magic gone wrong. Maybe a spell affected Harry's behavior in a way that made him act inappropriately towards Ginny, and her immediate reaction was to slap him in the heat of the moment.
It could be due to a situation where Harry made a decision that Ginny strongly disagreed with. Say, Harry decided to go on a very dangerous mission without consulting Ginny, and she felt betrayed and angry enough to slap him.
One possible reason could be miscommunication. Maybe Harry made a decision during the post - war rebuilding without consulting Ginny, and she felt left out or disrespected. For example, if he agreed to some dangerous mission without telling her.
One possible reason could be a growing apart due to their different career paths. Harry, being deeply involved in the wizarding world's security and Ginny having her own Quidditch career. Another reason might be the stress of living in the public eye. Their relationship may not be able to withstand the constant scrutiny and pressure from the wizarding community.
One possible reason could be that Harry has been spending too much time on his heroic duties and not enough time with Ginny. Another might be that he made a decision without consulting her, like taking on a particularly dangerous mission. It could also be something as simple as he forgot an important date or anniversary.
One possible reason could be the stress of Harry's fame. His status as 'The Boy Who Lived' might put a lot of pressure on their relationship. Constant media attention and public expectations could lead to arguments and a growing distance between them.
Well, it could be due to the stress of their relationship. Harry had a lot on his plate, being the hero and all. Ginny was also a strong - willed witch with her own ideas. They might have had an argument about their future together. For example, Harry might be worried about Ginny's safety if they stayed together, given his dangerous life. Ginny, on the other hand, could be frustrated that Harry was trying to push her away for her own good. Another possibility is that they could be crying over the state of the wizarding world. After all the destruction caused by the war, seeing their beloved Hogwarts in ruins or the wizarding community divided could be heart - breaking for them.
Maybe in fanfiction, Ginny discovers that Harry still has some unresolved feelings for Hermione. This could create a rift between them and lead to a divorce. It's not uncommon in fan - created stories to explore complex love triangles that were not fully resolved in the original series.
One possible reason could be that Harry is too focused on his fight against Voldemort and doesn't want to put Ginny in danger. He might think that being with her would make her a target for his enemies.
One possible reason could be that Ginny has seen Harry change a great deal during the war. Maybe the war has left Harry with a lot of emotional baggage that he's not dealing with well, and Ginny doesn't know how to handle it. So, she decides to give him some space by ignoring him for a while.
One possible reason could be that he might fear for Ginny's safety. In the wizarding world, there are always threats from dark forces. Harry has already lost many people he loves, and he might not want Ginny to be in more danger because of their relationship. Another reason could be that he wants to focus on his own personal growth and exploration. Harry has spent so much of his life fighting Voldemort and dealing with the wizarding world's problems that he may feel he needs time alone to figure out who he really is without the added pressure of a marriage.
It could be due to jealousy. Perhaps Ginny has been spending a lot of time with another character, and Harry misinterprets their relationship, leading to his anger. In fanfiction, the writers often play with such emotions to create drama.