The 67-year-old television personality was married to the 'Keeping Up With The Kardashians' star for 24 years until 2015 but Caitlyn - who was known as Bruce Jenner before she transitioned - admits that she wasn't entirely comfortable with the intimate relationship.
She wrote: "We fall in love quickly (we marry after seven months). Since - let's not kid ourselves - everyone wants to know, Kris and I have good and frequent sex at the beginning . [It was] imbued with love ... My attitude is no different than it was in high school: I'm just not entirely comfortable with it."
And the 'I Am Cait' star claims she told Kris about her "gender issues" before they got intimate.
Writing in her new memoir 'The Secrets of My Life' in an extract obtained by People magazine, she added: "I tell Kris about my gender issues before I make love to her.
"This will always be a subject of dispute between us. She insists that she was taken by surprise by my ultimate transition to Caitlyn, which obviously means in her mind that she did not know enough."
Meanwhile, Caitlyn previously insisted she will never have sex with a woman again.
Speaking about her thoughts on a potential romance, she wrote: "A future female companion? Yes, I do think about that. A future female sex companion? Not happening, at least for now, and perhaps not ever ...
"Of the most important things in my life, sex is beyond the bottom; it has been that way for a long time."
And while Caitlyn has "never" felt like enjoying a night of a passion with a male in the past, she is considering changing her ways.
She said: "I never had the inclination ... Maybe that attitude might possibly change if I have the Final Surgery."