As allegations that Tristan Thompson cheating on Khloé Kardashian surface,
The duo shared a sea of sizzling bikini photos from their vacation to Instagram late Tuesday and early Wednesday — some in honor of National Sibling Day.
“My sibling,” Kourtney, 38, captioned a shot of she and Kim walking on the beach. The picture had both in skimpy two-pieces, Kim’s bright pink and Kourtney’s gray-blue.
Kim, 37, meanwhile, posted a photo of two beach chairs overlooking the ocean, labeling the pic “chill.”
Later, Kim uploaded a photo of she, Kourtney, and pal Kristen Noel Crawley, all posing in their swimsuits on a golf cart.
“Ride or Die,” she wrote.
On Tuesday, news broke about Thompson’s alleged infidelity.
The 27-year-old NBA star was allegedly videotaped getting close to an unidentified woman on Saturday in a New York City lounge — while Kardashian is nine months pregnant with the couple’s first child, a baby girl.
Sources tell PEOPLE that Khloé’s family had reservations about Thompson from the start, worried he wasn’t a good match for the Revenge Body host.
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“When Khloé first started dating Tristan, her family questioned if it was a good idea. There were several concerns, including that he is another basketball player and also that his ex was pregnant,” a source told PEOPLE. “It took a while for the family to accept Tristan. They were worried that Khloé would end up heartbroken.”
The insider added, “Being on the road as an athlete, you face many temptations. But Tristan always assured Khloé’s family that he was totally committed to Khloé. Khloé thinks the world of Tristan.”
RELATED VIDEO: How Pregnant Khloé Kardashian and Tristan Thompson Are Passing the Time Until Baby Girl Arrives
A different insider confirmed to PEOPLE that Thompson was at the PH-D Lounge in Manhattan on Saturday ahead of the Cleveland Cavalier’s game against the New York Knicks on Monday. A man who has been identified as the athlete was seen speaking closely with a brunette in photos and footage published by the Daily Mail and TMZ. The Shade Room later published a video of Thompson and a brunette allegedly entering his hotel at 5 a.m.
TMZ also posted footage recorded in October 2017 allegedly depicting Thompson kissing one woman while a different woman groped him at the Darna hookah lounge outside of Washington D.C.
Kardashian and Thompson’s reps did not immediately respond to PEOPLE’s request for comment.