Footage emerged of Tristan appearing to kiss Lani Blair, during a night out at a NY club.
While the footage of Thompson may come as a shock to fans of the couple, it was rumored that the two began dating while Thompson's ex-girlfriend, lifestyle blogger Jordan Craig, was pregnant with his child.
"Tristan has been consistently cheating on Khloe", a source told People magazine. "He's a serial cheater".
TMZ also published surveillance tape Tuesday of the athlete kissing two women at a Washington, D.C. hookah lounge in October 2017, when Kardashian was three months pregnant.
The source added: 'They won't let any news change the importance of how attractive this birth is for Khloe'. To make matters worse, an alleged sex tape between Tristan and his NY side chick popped up alongside explicit text messages, which were deleted shortly after posting.
"They were there when I got there and they were part of a big group of friends". She and Thompson share 15-month-old son Prince Oliver together.
'Kris never expressed her fears to Khloe because she felt it would cause nothing but drama and create tension'.
'They were holding each other and it was so obvious'.
'As far as she knew, there were no negatives, ' the insider said. She was so ready to commit herself to the man she thought she'd spend forever with and he turned out to be no better.