Yes, there are likely fanfictions with such a plot. Fanfiction writers often explore alternative relationship dynamics in the Harry Potter universe. However, this goes against the canon where Harry ends up with Ginny.
Harry might be initially in shock. He can't believe Ginny would leave him and their child. He could become withdrawn, not really knowing how to deal with this new situation.
This is a very controversial and uncanonical concept for the 'Harry Potter' series. While there might be some fanfiction out there exploring such dark and untrue-to - the - original - story ideas, it goes against the essence of the relationships J.K. Rowling created. I personally don't support such fanfictions as they distort the well - loved characters and their relationships.
In this type of fanfiction, it could be that Harry has some unresolved issues from his past relationship with Cho. He sees Ginny as a distraction from dealing with those. But as time goes on, he can't ignore the pull he still feels towards Cho. He may leave Ginny when he realizes that he can't move forward in his life without exploring what could have been with Cho again.
The first consequence could be the breakdown of his friendship with Ron. Since Ron is Ginny's brother, he would likely be very angry at Harry for hurting his sister. Another consequence might be the division within the wizarding community. Fans of Harry and Ginny as a couple would be disappointed, and there could be a lot of speculation and gossip.
One possible reason in such a fanfiction could be a magical bond that forms between Harry and Draco unexpectedly. This bond might be stronger than his relationship with Ginny. It could be a result of a shared magical experience or a prophecy that ties them together in a way that makes Harry question his feelings for Ginny and ultimately choose Draco.
One possible reason could be miscommunication. Maybe they had a big fight over how to raise their child and Ginny, feeling unheard, decided to leave. Another reason might be external pressure. For example, if some dark forces were targeting their family again and Ginny thought leaving would keep Harry and the child safer. Or perhaps Ginny had some personal issues she couldn't deal with while being in the family, like feeling she lost her own identity in the relationship.
Ginny's character could develop in several ways. She may initially be heartbroken and feel lost without Harry. But as the pregnancy progresses, she could find an inner strength. She might become more protective, not just of her unborn child but also of her own feelings. She could also become more empathetic towards other single mothers in the wizarding world. This experience could make her a more complex and well - rounded character, no longer just the girl who was in love with Harry but a strong woman facing a difficult situation.
In Ginny and Hermione fanfiction, Ginny is often portrayed as bold and adventurous. She's not afraid to take risks and is very confident in her magical abilities. Hermione, on the other hand, is the brains of the duo. She's highly intelligent, studious, and always has a plan. Their combined characteristics make for an interesting dynamic. For example, in many fics, Ginny's impulsiveness might get them into a tricky situation which Hermione then uses her wits to get them out of.
One great fanfiction could be where Harry, Hermione, and Ginny go on a secret mission together. Maybe they discover a hidden chamber in Hogwarts that was unknown even to Dumbledore. They have to use their combined skills - Harry's courage and Quidditch skills, Hermione's vast knowledge, and Ginny's powerful magic - to solve the mystery within the chamber.