What's with the "whoever dates again first, wins" thing?

After a breakup why does it seem (I’m speaking generally here) that whoever dates someone new first “wins?” Is this a societal thing? Is it showing the other party that “HA! I am more desirable than you?” It’s some fucked up feeling of superiority?

I mean, I’ve definitely felt it, I just can’t quite get into the psychology of it all. Anyone? Discussion?