According to multiple reports, the 49-year-old Australian billionaire businessman dumped Carey after proposing marriage back in January.
"It's all over," a source told Australia's Woman's Day of the couple. "James had huge reservations about Mariah's new reality TV show and the fact that she was willing to expose their lives to the world."
A People insider echoed the same sentiment, insisting there was a falling out over Mariah's World-- which will premiere in early December 2016 on E! -- as well as their different lifestyles.
"Some of Mariah's eccentric ways, especially her spending habits, caused drama," the insider explained. "James is very private, and doesn't need the media to be successful. He doesn't want to be a part of Mariah's reality show."
Packer, however, allegedly allowed the singer and former American Idol judge to keep her massive 35-carat engagement ring.
"They are not together right now. They split a couple of weeks ago," another source told People, adding however, there might be a reconciliation down the road. "It's possible they will get back together. They are still talking, but James needed a break."
A third point of alleged contention was Carey's lack of a relationship with Packer's family members. Carey reportedly doesn't get along with Packer's mother, Roslyn, and was a no-show at his sister Gretel's 50th birthday party in Sydney, Australia, earlier this year.
Carey and Packer met and became friends at a 2014 movie premiere in Aspen and began dating in early 2015. They were first spotted together in June of that year in Capri, Italy.
This would have been the third marriage for both Carey and Packer, who has three children -- Indigo, Jackson and Emmanuelle Packer.
Carey's first marriage was to music producer Tommy Mottola, and then she wed America's Got Talent host Nick Cannon in April 2008. The Grammy-winning diva and Cannon welcomed twins Monroe and Morrocan in April 2011, but the pair ultimately filed for divorce in December 2014 after several months of separation.