The Prodigy frontman split with the Japanese DJ last year, contrary to earlier claims.
But it has been reported he tried to get back together with her, just days before his shock death.
Flint, 49, was found dead at his home on Monday in Dunmow, Essex – the house he once shared with Mayumi.
His bandmates later confirmed on social media that Keith had taken his own life.
Flint's house had been put on the market after the pair parted ways, but the listing was recently taken down.
According to The Sun, Flint had halted the sale of his house, in the hopes he could work things out with his wife.
A source claimed: "Keith always hoped they could make it work and he made various phone calls to her, pleading with her.
"But she didn’t change her mind and insisted they sell the house. It broke Keith. Mayumi isn’t to blame but it seems that Keith didn’t think he could carry on without her."
Mayumi was reportedly 6,000 miles away when Keith died performing a gig in Tokyo.
Mayumi's Twitter account shared a Japanese news story yesterday about Flint's bandmates heartbroken statement about his death.
The statement read: "It is with deepest shock and sadness that we can confirm the death of our brother and best friend Keith Flint.
"A true pioneer, innovator and legend. He will be forever missed.
"We thank you for respecting the privacy of all concerned at this time."
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