I personally have a couple friends who broke up and got together.
One broke up because he was interested in someone else. They were apart for a year. She got super awesome and he realized she was what he wanted. He begged and begged and she finally took him back. They are married now with a son and have great communication.
Another broke up and she moved across the country. She was insecure about him checking out different girls and he I don’t think was ready to settle down. They dated people here and there.. But they started talking again (he had their dog) and then did the long distance thing.. And she came back to visit and then stayed. They were apart for about six months. Now they are married with a son too.