However, Cho's best friend Marietta Edgecombe betrayed the D.A., and Cho and Harry's relationship fell apart. Cho remained loyal to her school and to the D.A., returning after she had graduated to participate in the Battle of Hogwarts. She survived the war and eventually married a Muggle.
Harry believed that Cho had betrayed them, leading the couple to break up. However, it was later revealed that Cho had unwillingly shared information about the group while under the influence of the Truth Serum.
In the film adaptation of Harry Potter and the Order of the Phoenix, the character of Marietta Edgecombe does not appear, and instead it is Cho who betrays the D.A. under the influence of Veritaserum.
In the film adaptation of Order of the Phoenix, Marietta does not appear and her betrayal is instead committed by Cho, under the influence of the Veritaserum potion. A Muggle-born student in Harry's year.
This betrayal had the biggest damage in the series as it made Harry an orphan, sealed Sirius in Azkaban for twelve years, and led to all the deaths shown in the future when the Wizarding War resumed.
Thus, their relationship was already strained when Marietta Edgecombe betrayed the D.A. and Cho stood up for her, angering Harry. After that, their relationship simply “fell apart”.
Because he wasn't romantically compatible with Luna or Cho. He had ONE date with Cho in which neither of them had a good time, and they really didn't have anything in common. Ron said it best; Harry needs someone more cheerful. And Cho needs someone who lets her be emotional.
The explanation is very simple - Harry has a very strong sexual desire for Ginny. He has no such feelings for Hermione. Sex is a fundamental aspect of adult relations. Sex is, in fact, the characteristic that defines the difference between a platonic relationship and a romantic one.
Harry had a teenage crush on Cho. She was pretty and a good Quidditch player, so he liked her for her looks and nerve—it's the kind of girls he likes anyway. It was only infatuation; there was nothing deeper there. When they gave it a try, it simply didn't work.
Ginny has no reason to hate Cho Chang, and unreasonable hatred is out of character for Ginny. She only ever displays a mild bit of jealousy when Cho offers to show Harry to the Ravenclaw Common Room in Deathly Hallows.
J.K. Rowling confirmed in an interview that Cho survived the Battle of Hogwarts and went on to marry a muggle, but this was not mentioned in the Deathly Hallows book or movie, leading to criticism of her character's treatment.
Rowling revealed more information about Neville when she stated that he married Hannah Abbott, a Hufflepuff classmate, who became the landlady of the Leaky Cauldron. The couple live over the pub, a fact that Rowling thought people would find "particularly cool".
Harry describes Umbridge to Sirius Black, saying that she's vile enough to be a Death Eater, despite not being one. Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.
Cedric was described as a fifth year in PoA, so he's a sixth year in GoF. He's described as “about seventeen” early in GoF, and he wouldn't have turned eighteen while still in sixth year, so his birthday was early in the school year, and he was about seventeen and nine months when he died.
Afraid that her mother's job was in jeopardy, and not convinced by Harry's interview in The Quibbler, she revealed the location of the D.A.'s meetings to Umbridge.
In desperation, Harry asks Parvati Patil, who accepts, and who suggests her sister Padma as a date for Ron. At the end of Harry Potter and the Half-Blood Prince, Harry realizes that anyone he becomes close to is likely to become Voldemort's target. To protect Ginny, he reluctantly ends their relationship.
In the epilogue, Draco marries Astoria Greengrass and has a son, Scorpius Malfoy. Draco's hairline has receded, making his face look even more pointed.
Why didn't Harry and the others forgive Cho Chang, after learning that she was forced to tell everything with a truth serum? In the books, it was Cho's best friend Marietta that betrayed them. She was not coerced. Instead, she went to Umbridge and told her about the D.A. and where they were meeting that night.
Dudley went on to get married and have two Muggle children of his own, who occasionally saw Harry's children. While the cousins remained in touch, it seems that Harry never got to see his Uncle and Aunt ever again. Harry Potter and the Cursed Child revealed that Petunia died due to unknown reasons sometime before 2020.
