The one that got away and the ones who slipped away

After writing the post about my ex boyfriend, I started thinking what made that break up different than all the others. I've had plenty of break ups, break ups started by me, when I've broken other hearts. But I went after this one three years later, but not the others. I call this one "The one that got away" but the other ones just slipped away. Why is this one different than all the others?