I posted part of this on another thread, but I think it fits in well on this one as well:
I have a friend who realized he had issues with anger and decided to contact the people in his life he felt he had hurt, which included an ex he broke up with about three years ago. After he apologized for his earlier behavior, they ended up speaking on the phone for about 3 hours and are now back together in a committed relationship. I am sure that is the last thing either of them expected after the ugly breakup and the fact that they hadn't communicated at all in the last three years.
I also have two friends who broke up about a year and a half ago for about six months. This was definitely a GIG situation with a happy ending. The two are now incredibly happy and plan to be married in October.
I think you just never know why, how, and when people will get back together. Sometimes it can have to do with the fact that we are able to work through our own issues and someone is just willing to give things another try.