Khloé Kardashian and Tristan Thompson 'Keep Things Friendly' for Daughter True After Split: Source

Khloé Kardashian "wants True to know that both of her parents love her tremendously," a source tells PEOPLE

Khloé Kardashian is keeping things amicable with ex Tristan Thompson.

A source tells PEOPLE that Kardashian, 37, and Thompson, 30, are not back together despite both being seen attending a birthday party for LeBron James' wife Savannah in West Hollywood, California, on Saturday night, as see in images shared by TMZ.

"Khloé and Tristan continue to keep things friendly. They were both invited to the birthday party and hung out a bit. They arrived with separate groups of friends though," the source says.

Throughout their breakup, Kardashian and Thompson are trying to keep 3-year-old daughter True as their No. 1 priority.

"They spent time together with True over the weekend as well. Khloé's goal is always to create the best situation for True," says the source.

"Regardless what happens with Tristan," the source adds, "Khloé wants True to know that both of her parents love her tremendously."

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On her Instagram Story Sunday, Kardashian shared a photo of herself with True, writing simply, "The only thing that matters."

In June, PEOPLE confirmed that Kardashian and Thompson had split amid rumors about the athlete's alleged infidelity.

Earlier this month, a source told PEOPLE that the Keeping Up with the Kardashian alum is not considering getting back with the NBA player, but she is still "happy" co-parenting True with him.

Tristan Thompson and Khloé Kardashian with daughter True. Tristan Thompson Instagram

"They get along well though. Khloé is happy co-parenting with him. She seems happy being single too," the source said at the time. "She is not interested in trying to have a relationship with Tristan right now. He can be very charming and he definitely keeps trying to get her back. She just won't go there. She seems to enjoy just focusing on True."

Though the exes are no longer together, a source told PEOPLE last month that Kardashian remains "very loyal" to Thompson.

"For now, Khloé is single and seems okay with it," the source said. "She continues to co-parent with Tristan and they spend time together as a family. Even though he has disappointed Khloé so many times, she is still very loyal to Tristan."