The pair are set to welcome their second child together via surrogate, with a representative for Khloé, 38, revealing the news just days ago.
But as the due date nears, Tristan was spotted holidaying in Mykonos this week, with reports he was partying at hotspot Bonbonniere.
It comes just days after it was announced the pair are expecting their second child.
The couple have famously endured an on-again-off-again romance over the last number of years, and are already parents to four-year-old daughter True.
Khloé recently split from the NBA star, 31, after his latest cheating scandal, which saw him father a child with fitness model Maralee Nichols.
Khloé and Tristan's second baby is thought to have been conceived prior to the news that Tristan had fathered a child with another woman.
A rep for Khloé said: "We can confirm True will have a sibling who was conceived in November.
"Khloé is incredibly grateful to the extraordinary surrogate for such a beautiful blessing. We'd like to ask for kindness and privacy so that Khloé can focus on her family."
Maralee Nichols announced that she had given birth to Tristan's child in December 2021, alleging that they had got together during his birthday celebrations back in March.
One month later, the basketball player confessed that he was the father, issuing a public apology to Khloe for his infidelity.
Posting to his Instagram Story at the time, he wrote: “Today paternity test results reveal that I fathered a child with Maralee Nichols.
“I take full responsibility for my actions. Now that paternity has been established I look forward to amicably raising our son.
"I sincerely apologise to everyone I've hurt or disappointed throughout this ordeal both publicly and privately."
Tristan and Khloe have been dating since 2016, and it has been far from smooth sailing. Numerous cheating scandals affected the relationship, including an infamous leaked clip appearing to show Tristan kissing a woman at a rooftop bar, just days prior to Khloe’s due date with True in April 2018.
While the pair reconciled, they split in February 2019 after it was alleged that Tristan was seen kissing Kylie Jenner’s former friend Jordyn Woods at a party.
Tristan is also dad to five-year-old Prince, who he shares with 30-year-old model Jordan Craig.
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