Perhaps in this fanfiction, Edward discovers that Bella has a hidden connection to his vampire past that Fem Harry doesn't have. This connection could be something like a long - lost relative who was involved in the creation of his vampire clan, which draws him towards Bella.
One possible plot twist could be that Edward realizes that Bella represents a more 'normal' life for him compared to Fem Harry. Maybe Fem Harry has some dangerous or complex magical powers that Edward fears, while Bella seems more human and easy to understand.
One possible plot could be that Edward, perhaps influenced by some dark magic or a misunderstanding, decides he has more in common with Harry. Maybe he sees Harry's courage and selflessness and feels drawn to that world. He leaves Bella heartbroken, and Bella then has to find a way to move on while Edward starts a new life in the wizarding world with Harry as his new friend or more.
Fem Harry might be heartbroken. She could initially try to win Edward back, using her magical abilities in creative ways. For example, she might create a magical memory of their time together to show Edward what they had was special.
A really interesting plot twist could be that Bella's pregnancy progresses at an extremely fast rate, and the baby has powers that allow it to communicate with Bella and Edward telepathically even before it's born. This causes them to reevaluate their relationship and what they thought they knew about vampires and half - vampire children.
One possible plot twist could be that the twins have some sort of special power. Maybe they can communicate telepathically from the womb, which causes Bella to have strange visions and Edward to sense something unusual even though he's left. Another could be that Bella discovers a hidden family secret about her own lineage that is related to the twins and their potential abilities. This could lead her on a journey of self - discovery while dealing with the pregnancy alone.
One possible reason could be that Bella discovers a side of Rosalie that she feels more connected to on an emotional level. Maybe Rosalie shows her a different perspective on the vampire world that Edward had been hiding from her. Another aspect could be that Bella has grown tired of Edward's over - protective nature and sees Rosalie as a more independent and free - spirited vampire to be around.
One possibility could be that Bella has to face the challenges of pregnancy alone. She might struggle with the physical and emotional changes while also dealing with the absence of Edward. The Cullen family could be in a dilemma about whether to support her or not, as Edward's departure might have left them with mixed feelings. And Bella could start to discover new powers or abilities within herself as she copes with the pregnancy, which could be a big part of the fanfiction plot.
The plot might start with Jacob being in a relationship or a strong friendship with Harry. But then, Bella enters the picture. Bella has some unique qualities that attract Jacob. As he gets to know Bella more, he starts to question his relationship with Harry. Eventually, he makes the choice to leave Harry. There could be a lot of emotional turmoil for all three characters. Harry might feel betrayed, Bella might be conflicted about getting involved with Jacob in such a situation, and Jacob has to deal with the consequences of his choice. In the end, it could lead to a new relationship between Jacob and Bella while Harry has to find his own way forward.
One possible reason could be that Paul represents a different kind of life for Bella. Maybe he is more down - to - earth compared to the often brooding Edward. Paul might offer a simpler and more straightforward relationship without all the supernatural drama that comes with Edward.
One possible reason could be that Bella discovers a different side of Jasper that she finds more appealing. Maybe Jasper shows a deeper understanding of her in some aspects that Edward lacks. For example, Jasper's past experiences might make him more empathetic towards Bella's own struggles in a way that Edward, with his own set of vampire characteristics, doesn't quite get.
For Edward and Harry's relationship, it's likely to be broken and filled with hurt. Harry might feel betrayed and angry. As for Edward and Bella's relationship, it could start off with a lot of drama. People around them might not understand or accept it quickly.