According to the source, just before their split, Carey and Packer were looking forward to planning their wedding. The former couple, who got engaged in January, planned to marry in the new year, and had gone to Greece to discuss wedding plans after her divorce from Cannon was finalized.
For his birthday on Sept. 8, Carey gifted Packer a Cartier wedding band, for which he thanked her and her manager Stella Bulochnikov with a note saying "I loved my birthday present," the source says, adding that both Packer and Carey loved sending each other extravagant gifts.
Carey's rep exclusively confirmed to ET last Thursday that the 46-year-old singer and Packer were on a break after getting into a fight during their Grecian vacation, however a source later told ET that the two had broken up, and are "very unlikely to work things out."
ET caught up with Cannon in July, where he slammed rumors that he was "holding up" Carey's wedding to Packer.
"That's clearly not the case," he said. "Who made that up? Who put that out there?"
"I wish it was that easy where you can just sign something and say, 'Oh, I'm done,' but it's a lot of things that go with that that are beyond my control," the America's Got Talent host explained. "The only thing that's important to me is my children. I want what's best for them. I believe my ex feels the exact same way."
Carey and Cannon -- who filed for divorce from in December 2014 -- are clearly still close. The two recently reunited for the singer's annual Halloween bash on Saturday.