Why did Simon break up with Clary Do they get back together?

Simon broke up with Clary because he felt that their relationship was complicated by their respective roles in the Shadow World and his desire for a more normal life. Additionally, he struggled with his feelings after turning into a vampire, which made it difficult for him to connect with her. As for whether they get back together, their relationship evolves throughout the series, and while they face various challenges, they maintain a deep bond and friendship that suggests a potential for reconciliation.