6. Bradley Cooper and Jennifer Esposito, 4 months
The Hangover hottie married the actress in December 2006, only to file papers in May 2007. The short-lived marriage might have messed him up in the commitment department - after the divorce, he dated Reneé Zellweger for a while. After that went south, he barreled through a handful of actresses, allegedly including Jennifer Aniston, Jessica Biel, and lately, Olivia Wilde.