What Led to Khloe Kardashian and Tristan Thompson Breaking Up Again

New cheating allegations took its toll on the relationship, a source tells ET.

New cheating allegations put an end to Khloe Kardashian and Tristan Thompson's rekindled relationship, a source tells ET.

Multiple sources told ET on Monday that the 36-year-old reality star and the 30-year-old NBA player, who share 3-year-old daughter True together, have called it quits. One source tells ET that Khoe and Tristan ended their relationship a few weeks ago, after new allegations against Tristan surfaced. Instagram model Sydney Chase claimed during an April interview that she hooked up with Tristan back in the fall, which he's vehemently denied. News of their most recent breakup also comes amid reports that Khloe threatened to take legal action against a woman who is claiming that Tristan fathered a child with her.

Khloe is reportedly suing the woman, Kimberly Alexander, for defamation, claiming that she fabricated direct messages to make it look like she and the reality star had a conversation over Instagram. Khloe's attorney, Lynda B. Goldman of Lavely & Singer Professional Corporation, claimed in court documents obtained by ET that "a DNA test from one of the nation's top labs confirmed that Mr. Thompson is not the father of [Kimberly's] child."

Still, according to the source, the new claims took a toll on the relationship.

"Khloe gave Tristan several chances and after new allegations decided it was time to break things off," the source says. "The two are on good terms and at the end of the day Khloe just wants True to have a good relationship with her father."

A second source tells ET that Tristan was acting "very single" at a birthday party in Bel Air on Friday.

"The Kardashians were invited to the party but did not attend," the source says. "Tristan and Khloe will continue to co-parent True together in a healthy, loving way."

Prior to their most recent breakup, Khloe and Tristan had already weathered two very public cheating scandals. The first one occurred in 2018, when reports broke that Tristan cheated on Khloe with multiple women while she was pregnant with True. Still, the two stayed together. But in February 2019, the couple broke up after reports that Tristan cheated on Khloe with her sister Kylie Jenner's former best friend, Jordyn Woods.

During the Keeping Up With the Kardashians: The Final Curtain reunion special -- which was taped in April and aired Sunday night -- Khloe opened up to host Andy Cohen about her on-again, off-again relationship with Tristan. Khloe said that she initially took Tristan back after his first cheating scandal because she was "overwhelmed" by all the media attention and pressure after welcoming her first child, but that following the scandal with Woods, it was a longer road to reconciliation. She said that they had only recently rekindled their romance after co-parenting together throughout the COVID-19 pandemic.

When Andy bluntly asked Khloe if she trusts Tristan now, she responded, "I mean, I definitely trust him as a friend and all those things."

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