Looks like Ashlee Simpson is a single lady once more. A source told Us Weekly on Nov. 27 that the single mom split from her boyfriend, Boardwalk Empire star Vincent Piazza. "There was no bad blood and no third party involved. It was honestly just a long distance relationship and it became too hard to make it work," the source explains. "It's not necessarily forever and they could get back together. Nobody is to blame. Just the distance." Simpson, who's mom to 4-year-old Bronx, split from ex-husband Pete Wentz in February 2011 and began dating Piazza in June that year.