Personally, I get over it. I can hardly remember times with old loves, obviously it all happened but it was a long time ago and we split because it couldn't work for whatever reason. Personally, I think when you hanker after a love in the way you and others have described, it's because of other issues within yourself. Something about that time made you like who you were and you're associating it with who you were with and the situation... That's just my personal take on things as I absolutely can't relate to clinging on to something that wouldn't or couldn't work. (Mind you, I also do not keep in touch with exes too much if at all, I believe it to be detrimental to yourself and frankly, an ex is not a friend, they're an ex, again, my personal take on break up).
I exclude mamy completely as I think the death of a loved one you were with for a long time is an entirely different kettle of fish.