03.
What about the one that got away?
Ok, I'm sorry if you got the Katy Perry's ear-worm in your head.
There are times where the person is your ex for a reason. However don't completely knock it. Typically what happens is that people leave their exes hoping that the grass is greener on the other side. Well sometimes it is, sometimes it's not, and other times it's only greener because it's fertilized with BS.
So what do you do about this? Getting the one that got away is a challenge in and of itself, but it can be done.