The 34-year-old television personality said in a series of Instagram Stories posts Tuesday she never knowingly cheated with Thompson during his relationship with Jordan Craig, the mother of his 2-year-old son, Prince.
"MY TRUTH IS: I met Tristan because HE CHOSE to go on a blind date with me. A mutual friend set us up," Kardashian wrote. "After going on some dates, Tristan told me that he had an ex that was pregnant. Obviously, I was reluctant about us continuing to date or start a relationship."
"He pleaded with me that the relationship was over long before we met," she said. "He had me talk with his most inner circle. He showed me physical poof (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."
Kardashian said she truly believed Thompson and Craig were no longer dating, but apologized for causing any inadvertent pain.
"This is my truth! The truth that I believed and trusted. 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!" the star wrote.
"I pray my truth is in-fact that. Lord knows I pray but now, I really don't know what to believe," she said. "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!"
Craig said in court documents obtained by Radar Online this week that Thompson cheated with Kardashian. Kardashian and Thompson were first linked in September 2016 during Craig's pregnancy.
Kardashian and Thompson welcomed their first child together, daughter True, in April 2018 following reports Thompson cheated during Kardashian's pregnancy. The couple reconciled but split again in February after Thompson reportedly cheated with Jordyn Woods.
"I know that she's very strong and I just feel like she's in a really good place," Kourtney said of Kardashian. "She's the best mom to her daughter and that's where all her energy is going."