Well, it could be that she and Ron had some irreconcilable differences. And the older wizard showed up at the right time, being more charming and understanding towards Hermione. He might have shared some unique views on magic or life that Ron couldn't offer. So Hermione, in this fanfiction scenario, decided to leave Ron for the older wizard.
At the beginning, Ron would likely be in shock. He had always thought he and Hermione had a special bond. After the shock, he might become a bit bitter. However, his friends, like Harry, would probably try to cheer him up and help him see that there are other things in life. Eventually, Ron might find a new purpose in his life, whether it's in his magical studies or in exploring new parts of the wizarding world, and try to move on from Hermione.
Perhaps in the fanfiction, Ron's jealousy gets the better of him. He might be jealous of Hermione's success or her friendships with other characters like Harry or some of her academic peers. His jealousy could manifest in ways that make Hermione feel suffocated or unappreciated, causing her to end the relationship. Also, Ron may have some habits that Hermione can't tolerate anymore. For example, his slacking off on certain responsibilities or not taking things as seriously as she does.
Yes, it can be a somewhat common plot twist in fanfiction. Fanfiction often explores alternative storylines and relationships. Some writers might use this plot to add drama or explore different character dynamics. They could be interested in seeing how Hermione's character would develop in a relationship with an older man, perhaps to give her a more mature or different kind of connection compared to what she had with Ron.
One possible reason could be that in the fanfiction, Bill might be depicted as more mature and worldly compared to Ron. Hermione may be attracted to his experience and the different perspective he can offer.
Often, the older man is portrayed as very sophisticated. He might be highly educated, perhaps a well - respected wizard in the magical community. For example, he could be a renowned scholar or a powerful figure in the Ministry of Magic. This makes him an attractive alternative to Ron in the eyes of some fanfiction writers who want to show Hermione being drawn to a more worldly and accomplished partner.
The relationship changes drastically. Hermione may start to view Ron as someone she once knew well but has now grown apart from. Ron, on the other hand, may go through a range of emotions from denial to anger to sadness. Their friendship that was the foundation of their relationship may also be damaged, and they may have to re - evaluate how they interact with each other in the wizarding community.
In fanfiction, this kind of plot twist can be really interesting. It might be due to the author wanting to explore different character dynamics. Maybe Hermione realizes she has a stronger connection with Sirius in terms of his more adventurous spirit or his different life experiences compared to Ron.
Perhaps in the fanfiction, Hermione leaves Ron because of his jealousy issues. Ron has shown bouts of jealousy in the original series, and if that continued to be a problem in the fan - created story, it could be a major factor. For example, if Hermione started to gain more recognition in the wizarding community for her intelligence and contributions, and Ron couldn't handle it well. Or it could be that new characters were introduced in the fanfiction, and Hermione developed a stronger connection or friendship with them, which made her re - evaluate her relationship with Ron.
It could be that the fanfiction depicts Ron in a negative light that Hermione doesn't agree with. She has a complex relationship with Ron, and while they may have their differences, she doesn't like to see him misrepresented. If the fanfic makes Ron look like a fool or a jerk in a way that doesn't seem fair or true to the original character, Hermione would likely be disgusted.
The relationship between Hermione and Ron in this fanfiction takes a sharp turn. It goes from a relationship (presumably) full of the usual bickering and affection they have in the original series to a complete break - up. Hermione's feelings shift towards Bill, leaving Ron behind.