In such a fanfiction, Harry might first feel shocked and betrayed. He could distance himself from Ginny immediately. Then, he might focus more on his friends and his own personal growth, perhaps delving deeper into his magical studies or his role in the wizarding world. He might also struggle with trust issues in future relationships.
Well, it could be that Harry has started acting really distant from Ginny. He might be canceling their dates frequently or not being as affectionate as he used to be. In the fanfiction, Ginny might also find some strange gifts or notes that she suspects are from another girl to Harry, which makes her think he's cheating.
She could start by apologizing sincerely. A heartfelt apology is the first step. Just telling Harry how sorry she is for her actions and how much she regrets it.
One possible reason could be miscommunication. Maybe Ginny feels neglected by Harry because he's so caught up in his own heroic deeds and doesn't pay enough attention to her. So she might seek comfort or excitement elsewhere.
In fanfiction, anything can happen. However, if Ginny cheats on Harry, it would likely shatter the trust in their relationship. It could lead to a downward spiral in the story, with Harry feeling betrayed and perhaps seeking revenge or just distancing himself. This could also change the dynamic among their friends and family, as everyone would be caught in the middle of this drama.
There's also 'Caught in the Act'. This fanfiction delves deeper into the reactions of their friends when they see Harry and Ginny snogging. It's interesting because it shows different perspectives, like Hermione's initial shock and Ron's teasing. The descriptions of their relationship are really sweet and in - character.
I really hope there isn't such a fanfiction. Ginny and Harry have a strong and loving relationship in the original story, and creating a fanfiction with such a negative and unfaithful plot goes against the essence of their relationship.
After being caught, they could be forced to keep their relationship more low - key for a while. This might involve sneaking around more carefully. They may also have to deal with the opinions of others, like Harry having to face the Weasley family's concerns about their relationship. Ginny would have to assure her family that Harry is the right person for her.