According to a Tuesday report from TMZ, the Keeping Up With The Kardashians star spent Valentine's Day with Thompson and their 10-month-old daughter True in Los Angeles - but just four days later the Cleveland Cavaliers basketball player was getting intimate with Kylie's 'wifey' Jordyn at a private party in his LA home.
A Hollywood Unlocked contributor who was present at the bash spotted 27-year-old Tristan "making out" with the 21-year-old Instagram model.
Hollywood Unlocked also reported the pair "couldn't keep their hands off each other" and confirmed the interaction certainly wasn't just friendly.
Jordyn, who is a model and brand ambassador for Khloe's Good American clothing line and has been best friends with Kylie for years, is said to have remained in the house with Thompson until 7am.
In a since deleted tweet, Tristan denied rumours branding them "fake news" - but it seems Khloe's best friend Malika Haqq has a different view of the scandal.
The Kardashian satellite seemingly confirmed speculation by commenting "STRONG FACTS" on Hollywood Unlocked's Instagram post about the affair.
Family friend Larsa Pippen also wrote "Amen!" while Khloe herself left a series of shouting emojis alluding to the accuracy of the post.
This isn't the first time Thompson has been embroiled in relationship controversy.
Days before Khloe gave birth to True in April 2018, the Cavs' centre forward was caught cheating on her with a series of women in video footage obtained by Daily Mail.
But despite Tristan's past (very public) indiscretions, a source close to the Kardashians told US Weekly that the latest revelation of infidelity is "completely shocking" to Khloe who "loved Jordyn before this".
The sensational claims come days after Jordyn helped Kylie celebrate her daughter Stormi's first birthday with an exotic, sun soaked getaway and an extravagant carnival themed party.
Back in June 2018, the billionaire business mogul revealed Woods lives with her and views her as a second mother to baby Stormi.
The BFFs also recently collaborated on a makeup line for Kylie Cosmetics.
Of her relationship with the youngest of Kris Jenner's children, Woods has said: "We're very much the same, but we're also vey different. i think that's what makes us best friends and we are always on the same page about things."
Only time will tell if the inseparable duo remain on the same page about the latest Kardashian scandal.