Ashlee Simpson, Vincent Piazza Split

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The distance proved to be too much for Ashlee Simpson and Vincent Piazza.

The singer/actress and the actor have split after a year and a half together, a source close to the couple tells Us Weekly.

"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."

The pop star, 28, and the Boardwalk Empire star were first linked back in June 2011. By September, Simpson had already met NYC native Piazza's parents. (The group hung out together at the Emmy Awards that year.)

"She's a wonderful girl," Piazza told Us earlier that month during the premiere of his HBO hit.

 Prior to dating Piazza, Simpson was wed to Fall Out Boy rocker Pete Wentz. (The pair have a son together, four-year-old Bronx.) Their divorce was finalized in November 2011.