No one dates down. There's no question that nearly everyone in Hollywood comes from the better half of the gene pool. But it's no secret that some celebrities rank higher on the "hot or not" scale than others. And people in the entertainment industry often choose to date among their A-list peers. Yet it's a matter of time before a celebrity links up with a partner who's way out of their league. So from Katy Perry getting the boot from Russell Brand to Calvin Harris kicking Taylor Swift to the curb, these celebrities who dumped hot partners definitely regret their decision.