The Australian billionaire businessman was so desperate to wed the 46-year-old pop star, whom he has since split with, before March - three months after they got engaged - that he was willing to lose half his estate just to make her happy.
Speaking to 'Entertainment Tonight', a source explained: ''He [James] felt that ultimately he didn't need a prenup. He was going to marry her [Mariah] without a prenup. He loved her so much and wanted to make her happy.''
Despite not having an official prenuptial agreement in place, the 'We Belong Together' hitmaker believes she's entitled to $50 million because she had to uproot her life and move to Los Angeles so that James could be close to his children.
An insider explained: ''He moved her across the country and relocated her and her kids. He made promises to her that weren't fulfilled.
''This whole $50 million thing and other noise is a distraction to try and rationalise what she is asking for in terms of asking for an inconvenience fee.''
Although Mariah was still married to her husband Nick Cannon, with whom she has five-year-old twins Moroccan and Monroe, up until earlier this week, the pair had still decided on the wedding location of Bora Bora and, splashed out on a designer dress.
The insider explained: ''Mariah had a wedding dress at that point from Valentino couture and she had a mini version made for Monroe.
''Mariah is festive and wanted multiple weddings. She was planning multiple weddings and multiple ceremonies with James.''
Mariah was left heartbroken last month after James called off their engagement following a blazing row in Greece and refused to speak to her afterwards.
A source said: ''The split has been devastating for Mariah. She loved James and was planning to marry him. She made life changes for this man to prepare for their future as husband and wife, even relocating to Los Angeles at James' request, so he could be closer to his children.''
The pair - who began dating last year and got engaged in January 2016 - are yet to speak face-to-face since their row but are reportedly keen to meet up and discuss their differences after news of their shock split began to spread like wildfire.
The insider explained: ''Mariah would like James to apologise for breaking up with her so publicly. She feels like he used her to increase his profile in America and globally to help further his business interests.''
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