She also described the lengths Thompson went to in order to show her that he was single. "He pleaded with me that the relationship was over long before we met," she wrote. "He had me talk with his most inner circle. He showed my physical proof (correspondence between the two) and had me on calls with his lawyers to prove his point. His best friends, business associates and even his mother told me, him and his ex were broken up before we met."
The Keeping Up With the Kardashians star then insisted that this was her side of the story and apologised if any of Thompson's claims were false. "This is my truth! The truth I believed and trusted," she said. "If for any reason this is NOT, in fact, the truth, I am so completely and utterly sorry that TRISTAN and his inner circle would lie on something like this! I pray my truth is in-fact that. Lord knows I pray but now, I really don't know what to believe. Truthfully, from the deepest parts of my soul, I am sorry!"
"I'm sorry for any pain that has been created either way. No woman deserves to go through anything like this! This is MY TRUTH."
Kardashian and Thompson first sparked romance rumours in September 2016. Craig gave birth to a baby boy, Prince Oliver Craig Thompson, in December of that year.
Thompson would then welcome a baby girl, True Thompson, with Kardashian in April 2018. However, just days before the birth, Thompson was accused of cheating on Kardashian. He then made headlines over another cheating scandal involving Jordyn Woods earlier this year.
Kardashian and Thompson have since ended their relationship.
WATCH: Khloe Kardashian Toasts Jordyn Woods And Kylie Jenner On KUWTK.