It could be due to a fundamental shift in their relationship. After having a child, they might have realized that they no longer had the same feelings for each other as they did before. The stress of raising a demigod child, with all the potential threats and challenges, could have magnified any existing issues in their relationship. Maybe Annabeth felt that she needed a more stable and present partner, and Percy wasn't able to fulfill that role.
Perhaps Annabeth found that Percy was becoming too reckless in his actions, especially when it came to protecting their child. She might be worried that his behavior would put their family in danger. Or, it could be that Annabeth was feeling neglected. With Percy often being away on quests, she may have felt like she was shouldering most of the parenting duties alone and decided she couldn't take it anymore.
One possible reason could be that they grew apart over time. Maybe their different responsibilities in the demigod world led to a lack of communication and connection. Another reason could be external pressures, like the expectations of their respective families or the demigod community. It could also be that they had different ideas about how to raise their child, which caused irreconcilable differences.
The child will likely experience a great deal of emotional turmoil. Losing the stability of a two - parent home can be very difficult for a child. They may feel confused, sad, and even abandoned. The child might also start to question their own self - worth, wondering if they were the cause of the divorce.
Well, in some fanfiction, it could be due to a misunderstanding. Maybe Percy did something that Annabeth misinterpreted as a betrayal, like not being honest about a new power he discovered. This lack of trust then led to their break - up.
One possible reason could be a misunderstanding. Maybe there was a miscommunication between Annabeth and Percy about their future plans or how to raise their child. Another reason might be some external threat that Annabeth believes she can face alone to protect her family, so she leaves them behind. It could also be that she has some personal issues to deal with, like an identity crisis, which makes her think she's not fit to be with them for the time being.
Perhaps there are external factors at play. The world of demigods is full of chaos and danger. Reyna might be in a position where Percy feels he has to be by her side to protect her or to fulfill some greater prophecy that involves the two of them, and this leads to him leaving Annabeth.
One possible reason could be jealousy. Maybe Percy gets more attention or recognition in their fictional world that makes Annabeth envious and thus appear to hate him.
Annabeth could be under some kind of magical influence. In the Percy Jackson universe, there are many magical elements. She could be cursed or charmed without her knowledge. This would be a very interesting take in a fanfiction as it would add an element of mystery and also give her a chance for redemption once the truth is discovered. Also, it could be that she has some internal insecurities that she hasn't dealt with and they manifest in this way, making her act out of character.
Well, one possible reason could be that Percy made a really stupid decision without consulting Annabeth first. Like, if he went off on a dangerous mission on his own when they were supposed to be a team. Annabeth is a very strategic person and she might feel betrayed or extremely frustrated by such actions.
It could also be due to some sort of magic or mind - control. A powerful enemy might have cast a spell on Annabeth, forcing her to turn against Percy. In this case, it's not really her own will but the result of external manipulation.
In some fanfictions, Annabeth could abandon Percy because of a prophecy. If the prophecy seems to imply that being with Percy will lead to a great disaster, she might choose to leave to protect him or the world. Also, it could be due to a personal growth arc for Annabeth. She may realize that she has been too dependent on Percy in the past and decides to go off on her own to find her true self, leaving Percy behind.
One possible reason could be a misunderstanding. Maybe Percy did something that Annabeth misinterpreted, like being overly friendly with another character which made her jealous and led to her rejection.