Perhaps in the fanfiction, Edward breaks up with Harry due to a lack of communication. They might have busy lives and gradually stop sharing their thoughts and feelings with each other. As a result, small issues build up over time and create a rift between them. Or it could be that Edward has fallen out of love. Love can be fickle, and he might have met someone else who makes him feel more alive and attracted, causing him to end things with Harry.
One possible reason could be that Edward feels he is putting Bella in too much danger. In the 'Twilight' universe, his vampire nature attracts various threats. Another reason might be that he realizes their different life expectancies and doesn't want Bella to have a future filled with sorrow. Maybe he also fears that his control over his vampire instincts might fail one day and he could harm her.
One possible reason could be Harry's fear for Ginny's safety. In the wizarding world, he has so many enemies, and he might think that being with him puts Ginny in constant danger. Another reason could be his own insecurities. Maybe he feels he's not good enough for her despite all his achievements. He might also be so focused on his fight against dark forces that he believes he can't give Ginny the time and attention she deserves.
It could be because of the pressure from their respective families or the wizarding society. Their relationship was already controversial, and the addition of a pregnancy might be too much for Harry to handle. So, he decides to break up rather than face all the potential problems.
One possible reason could be that Bella realizes she wants a more normal life. In the Twilight series, Edward's vampire nature brings a lot of danger and secrecy. Maybe in the fanfiction, Bella gets tired of constantly being in the middle of vampire - related dramas and decides she can't handle it anymore.
Well, perhaps in the fanfiction there is a power struggle within the alliance. Harry, being a central figure, might not want to be part of a group where there is constant jockeying for power. Also, new revelations about the alliance's past actions or connections could make Harry want to distance himself. For instance, if he finds out the alliance has some shady dealings with dark wizards in the past, he would surely break the alliance to protect his own integrity and that of his true friends.
One possible reason could be differences in their future goals. Naruto is highly focused on being Hokage and protecting the village, while Hinata might want a more peaceful, family - centered life. Maybe Naruto's hectic schedule and constant danger make Hinata feel neglected, leading to their break - up.
It could also be related to his relationships. Perhaps he has an argument with Hermione or Ron, or he's having trouble in his love life. Fanfiction often explores the characters' emotional sides, and relationship problems are a common source of distress. So, walking on the street, these thoughts might flood his mind and lead to his breakdown.
One possible reason could be differences in their long - term goals. Maybe Chloe wants to pursue a more stable life while Beca is all about taking risks in her music career. This disparity in their future plans might lead to a break - up.
Well, in fanfiction, sometimes it's about exploring different relationship dynamics. The writer might be interested in how the relationship between Edward and Harry would change if such a betrayal occurred. It could also be a way to introduce new characters into the story. For example, the person Edward cheats with could bring in a whole new set of plotlines and interactions. Also, it could be a way to show the darker side of Edward's character, perhaps exploring themes of jealousy, insecurity, or self - destruction.
One possible reason could be miscommunication. Maybe they didn't understand each other's feelings and needs clearly. For example, Harry's preoccupation with his fight against Voldemort might have made Cho feel neglected.