Perhaps there is a conflict within the Stark organization. There could be other members who don't trust Peter or there are internal power struggles. Peter, not wanting to be caught in the middle of this chaos, chooses to leave. He may feel that he can better serve the city and protect the people by operating independently.
One possible reason could be a difference in ideology. Maybe Peter Parker feels that Stark's methods are too extreme or not in line with his own moral compass. For example, Stark might be involved in some projects that Peter doesn't agree with, such as using certain unethical technologies in the pursuit of justice.
It could also be for personal growth. Peter might realize that he has become too reliant on Stark and his resources. He wants to stand on his own two feet and prove that he can be a hero without Stark's constant guidance and support. So, he decides to leave to find his own way in the superhero world.
It might be due to a self - sacrificing decision on Harry's part. He could believe that by leaving, he would protect the Weasleys from the dark forces that are constantly after him. Since he has so many enemies, he might think that as long as he is around the Weasleys, they are in danger.
One reason could be that Peter realizes he still has unresolved feelings for Gwen from his past. Maybe something happens that makes him remember their relationship more vividly.
One possible reason could be a misunderstanding with his friends in Gryffindor. Maybe there was a big argument over something like a Quidditch match strategy that made him feel alienated.
One reason could be that he feels ostracized. Despite his efforts to protect Konoha, some villagers still look at him with suspicion because of the Nine - Tails inside him. He might just get tired of constantly having to prove himself and decide to leave in search of a place where he can be accepted for who he is.
One possible reason could be extreme exhaustion. Peter Parker has a double life as a student and Spider - Man. He might be overworked, not getting enough sleep, and his body just gives out. For example, he could have been fighting multiple villains in a row without a break.
Well, one reason could be that he's on a secret mission for S.H.I.E.L.D. that requires him to go undercover and cut off all contact. Maybe he's investigating a new super - villain threat that's too dangerous to let anyone know about.
One possible reason could be a difference in ideology. Maybe Spider - Man has a more local - friendly approach to crime - fighting while the Avengers are often involved in large - scale, global threats. He might feel that his skills are better utilized in his own neighborhood, like Queens, rather than in the grand, often cosmos - level battles of the Avengers.
A reason could be that Peter is reminded of Tony's last words to him. Those words were full of hope and trust in Peter. When Peter reflects on them, he is overcome with emotion and starts to cry as he feels the weight of Tony's expectations.
One possible reason could be a disagreement over superhero tactics. Peter, being young and idealistic, might yell at Tony if he thought Tony's methods were too extreme or not in line with his own sense of justice. For example, if Tony made a decision during a battle that put civilians at risk, Peter would likely be very vocal about it.
One possible reason could be ideological differences. Maybe she discovers some practices within the Order that go against her moral compass. For example, if the Order starts to use unethical magic in their fight against the dark forces, Hermione, with her strong sense of right and wrong, might not be able to tolerate it and decide to leave.