Revealed; Real reason Mariah Carey is asking billionaire James Packer for $50m

It has been revealed Mariah Carey has demanded $50 million from ex-fiance James Packer because that is the amount she would have walked away with had they signed their prenup.

TMZ has seen an email chain from back in mid-February going back and forth, from Mariah's team to Packer's. 

The billionaire was clearly itching to tie the knot with Mariah, upset that his people were not moving fast enough to nail down the prenup so he could marry her on March 1st in Bora Bora.

Packer's lawyers clearly felt the prenup was complicated, sending Mariah's team a 100 page document outlining the specifics. 

Among the many conditions ... if Packer gave Mariah a piece of jewelry or anything else, she would have to give it back if they broke up unless he sent her a signed note saying it was a gift.

The prenup draft also provided that Mariah would get $50 mil if they broke up.

Packer's lawyers were telling him they could not get the prenup signed, sealed and delivered by March 1st. His response ... 

"I don't know who's working for who because there are a lot of names I haven't heard before on this email chain. The people who work for me -- message -- do as I say or f*** off. I want to get married on March 1st. James."

We're told at the time of the email chain, Mariah already had a dress, the flowers were ordered and all the flights for the guests were secured.

The prenup was never signed, and Mariah believes that's when his people started trying to tear them apart.