Ever since the indiscretions of Tiger Woods and Jesse James, the tabloid magazines have gone on a witch-hunt to find the next cheating celebrity whose ensuing scandal and crumbling marriage will help boost their sales. And, now, with 4 tabloid magazine covers devoted to his supposed cheating, it looks like Ashton Kutcher might be a contender. Although there have been many reports of Ashton admiring his young co-stars like Natalie Portman and Katherine Heigl (He once even told Howard Stern that on-screen love scenes were like “free cheating,”) Star Magazine was the first to allege that Ashton’