It does happen, my uncle and my aunt have gotten through thick and thin, despite breaking up in the past. They got back together and continued on with the relationship for years.
2nd story: They were college sweethearts in the first year. Unfortunately distance played a role alonside with their hectic school schedules. Eventually they broke it off. 4 years later the met up, got back together, and have been married for 2 years!
3rd story: Close friends, they went out for close to a year before the girl ended it with the boyfriend. Boyfriend was confused for the most part, the girl was devastated as witnessed by me. A few months later, they meet up, get back together and are still going on strong for their technical 3 year anniversary!
Getting back together really does happen. As long as both parties are mature about the break up, mind games aren't played, and most importantly a period of positive change and growth has occurred.
Good luck to everyone!