Nearly six months after NBA star Tristan Thompson was busted cheating on Khloe Kardashian a few days before she gave birth to their daughter, the reality TV star is "struggling with trusting him to be on his own around other women when she isn't there," a source tells E! News.

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Khloe is also "still very much insecure" when they're apart, the E! source adds, which is happening more often now that the Cleveland Cavaliers star is back in Ohio and on the road for preseason games after spending the summer in Los Angeles with Khloe and their daughter, True.

On Oct. 5, People magazine reported that Khloe had scrapped plans to return to Cleveland with Tristan as he settles in for the new NBA season. "It's of course difficult to trust someone 100 percent who cheated days before he was about to become a dad," an insider told People. "She wants to move back to Cleveland, but she isn't sure what date she is [going]. The move is postponed for now. She seems very upset about leaving her family. She had the best summer in L.A."

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According to E!, after months of standing by Tristan in the wake of his betrayal, Khloe's now at a place where she's again questioning how to best move forward. "Khloe has had many ups and downs lately with Tristan," the source explained, adding that the Good American designer and the basketball player "are not in the best place currently."

Khloe wants to make the relationship work for her daughter's sake, the source added, "but it has been very difficult recently. She has huge trust issues that she has not overcome, and it's definitely caused a rift. Khloe thought things would blow over, but she still has insecurities deep down."

In the weeks immediately following Tristan's cheating scandal -- and Khloe's decision to stay with him -- her famous family made it clear they were unhappy with how things were playing out, though the vowed to support her. That's continued to weigh on Khloe, E! reports.

"In addition to her own insecurities about Tristan's infidelity, Khloe is continuing to struggle with her family's thoughts of Tristan as most of them haven't forgiven him for cheating, even though they are trying to support Khloe's decision to be with him," the source explained.

"Everyone in the family ultimately wants what's best for True, but they're wary that Tristan will cheat again, and they hate seeing how this is affecting Khloe," E!'s source added.

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Over the last few weeks, fans have taken notice as Khloe's posted a whole lot of inspirational -- and cryptic -- quotes on social media, leading many to believe that she's referencing her private struggles. In recent days, as Cosmopolitan has reported, she's written about being "brutally broken" and told fans "Don't ever feel bad for making a decision about your own life that upsets other people."

She also just posted a message giving a "Shout out to everyone making progress that no one recognizes because you never let anyone see your darkest moments." She continued, "You've been silently winning battles and transforming yourself, be proud of every step you're making in the right direction. Keep going because you got this."