If you love someone, set him free... If he comes back, he's yours. If he doesn't, it was never meant to be...
NEW VERSIONS:
Pessimist: If you love someone, set him free... If he ever comes back, he's yours. If he doesn't, as expected, he never was. Whatever gave you the idea that he would anyway?
Optimist: If you love someone, set him free... Don't worry, he'll come back.
Suspicious: If you love someone, set him free... If he ever comes back, ask him why.
Impatient: If you love someone, set him free... If he doesn't come back within a week forget it.
Statisticians: If you love someone, set him free... If he loves you, the probability of him coming back is high. If he doesn't, your relation was improbable anyway.
Patient: If you love someone, set him free... If he doesn't come back, put your life on hold and sit and wait.
Playful: If you love someone, set him free... If he comes back, and if you love him still, set him free again... repeat*