Ashlee Simpson and Pete Wentz
After three years of marriage, Jessica Simpson's little sis and the former Fall Out Boy bassist called it quits in 2011; The couple had son Bronx in 2008. "Ashlee's been my best friend for five years," Wentz told KIIS-FM shortly after their divorce. "She's the mother of my child. I have nothing but love and respect for her and going through something like this isn't easy, but we're friends and the most important thing is to put our son first."