Although Justin Bieber and the Selena Gomez journeyed to Puerta Vallarta, Mexico for a New Year's trip, their happy holiday was cut short when Gomez abruptly flew home to Los Angeles on Dec. 30. "They had another huge fight, and Selena won't forgive him," an insider tells Us Weekly of the perpetually on-again, off-again pair.

It certainly seems final this time -- with Gomez spending New Year's Eve at an L.A. house party with pals, while Bieber rang in 2013 with rapper pal Lil Twist at L.A. club Couture, where he flirted with various girls. "He's been really down about the breakup," a source admits.

Citing Bieber's "bad influence," another pal insists: "Selena is done with him."

VIA: US WEEKLY