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.
People reports that Jordyn just moved out of Kylie Jenner's house—and is leaning on her family for support.