According to a report in Australia's Women's Day magazine, the businessman has allegedly called time on his engagement to the 46-year-old singer because she became obsessed with her reality television show 'Mariah's World', and was "willing to expose their lives to the world" in a way he wasn't comfortable with.
A source claimed: "It's all over. 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."
Another source alleged that James was tired of the 'Without You' hitmaker's "extravagant spending".
The insider added: "James is very generous, but Mariah takes it to the next level."
And the 49-year-old billionaire - who has been in a relationship with the 'Touch My Body' singer since June 2015 - has reportedly even let Mariah keep the lavish $10 million engagement ring he gave to her when he proposed in January.
It was also claimed that problems surfaced when the chart-topping singer didn't attend a birthday party for James' sister.
The source said: "When she refused to come to Australia for [Packer's sister's] birthday party it created a lot of tension in the family. James' tight circle of friends never really thought they would marry."
The news comes just days after the 'We Belong Together' musician cancelled shows in Chile, Argentina, and Brazil as part of her upcoming tour in South America, citing "promoter negligence" as the reason for the cancellation.
She said previously: "To all of my lambs in South America, I am devastated that a portion of this tour had to be cancelled. Thank you for all of the excitement and love--I hope to see you soon, my darlings!"