Justin Bieber and Selena Gomez Split Before NYE: Mistrust in Mexico?

Justin Bieber and Selena Gomez have split up again following a blow out fight that the couple had in Mexico shortly before New Year's Eve.

The tumultuous couple, who has been dating for three years, had reportedly traveled to Mexico together to ring in the new year, but a fight allegedly broke out on Dec. 30, forcing them to go their separate ways, according to The New York Daily News.

"They keep breaking up and getting back together," an insider told The Daily News. "It's an on-again, off-again relationship. It's probably not correct to characterize this as a final breakup."

Bieber, 18, and Gomez, 20, reportedly ended their relationship then and there and have not seen each other since.

"Selena left Mexico that same day and Justin left for L.A. on the 31st. They haven't seen each other since," a source reportedly told TMZ.com.

It is still unclear what exactly triggered the argument, although the singers have a history of fighting over trust issues. The pair had previously split up in November following speculation that Bieber had been texting other girls.

"The problem in the first place is that Selena was a little bit of a jealous girlfriend and Justin wasn't really taking her feelings into regard," a source close to the stars previously told Radar. "Justin doesn't see texting other girls as cheating, but he's promised Selena he'll stop if she takes him back."

Several media outlets had reported that their November split may have involved a Victoria's Secret model, although the reports have never been verified.

Gomez took to social networking site Twitter just two days after her break-up with Bieber and the Disney star appeared to be optimistic about her future despite her relationship woes.

"New beginnings. Fresh start. I love you all," Gomez tweeted Jan. 1.