Jenner and the Kardashian matriarch Kris split back in 2014, when a source close to the famous family told the magazine the break "was a long time coming", following some years of differences between the pair. So at least she isn't being caught off guard when the thing hits bookstores.
While she writes sex with Kris was "imbued" with love, Caitlyn admits she was not always 100 percent okay with it.
Caitlyn also claims she had 36B-cup breasts, due to hormone therapy, when she met Kris in 1990.
Tensions between Caitlyn and Kim, Kourtney and Khloe Kardashian and Caitlyn have been frayed ever since she slammed Kris in her bombshell Vanity Fair interview two years ago.
"This is the last straw", the source told Us Weekly.
She also discusses how much Kris knew about her gender identity struggles. 'They feel completely betrayed, ' an insider told InTouch this week.
Sisters Kim, Kourtney and Khloe Kardashian are said to be outraged that Cait has spoken out about their late father and his involvement in what was dubbed the trial of the century.
It has been leaked that Jenner wrote in The Secrets Of My Life that Robert knew OJ Simpson was guilty of murder, but he worked with the athlete anyhow. She's dead to them'.
The Keeping Up with the Kardashians star got an advance copy of Caitlyn's book and is angry it talks about their sex life and paints her in an unflattering light. She has reportedly started to consider the idea of having sex with men since her gender reassignment surgery in January. "All these life decisions and she hasn't involved anyone but her new friends", said a source.
Kris is now "ballistic" that Cait has used the family's fame to make her book a best seller.