*puts hand up as an elligible lustie*
Definitley be happy for the good times and move on. Obviously you can be gutted etc, but when it comes down to it, being depressed and speding hours/days/months/years dwelling on it is hours/days/months/years you miss out on in your life.
I watched my Mum long for my father for 10 years before she found someone else, and even now she is still has difficulty getting over it. Its just not worth mentioning Dad around her, whereas if she just got over it and moved on she would have been much happier etc sooner.