Rob and Chyna s reality series will premiere this fall
Credit: Gabe Ginsberg/Getty

It’s no secret that Rob Kardashian‘s sisters didn’t exactly welcome his fiancée Blac Chyna to the family with open arms.

After all, Chyna, who was once a pal of Kim Kardashian West‘s, made waves after she took up with Rob while Kylie Jenner was dating Chyna’s ex, Tyga. (The former couple has a 3-year-old son).

“Khloé had the most issues with the relationship,” an insider tells PEOPLE in this week’s issue. “She found Chyna in her kitchen [when she started dating Rob] and didn’t know what was going on. She felt very disrespected.”

For much more on Rob Kardashian, pick up the new issue of PEOPLE, on stands Friday

Now, the tides are changing, namely because there’s no denying the positive impact that Chyna has had on Rob’s life. (The engaged couple will welcome their first child this fall and production on their reality series, Rob & Chyna, is underway).

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“The girls literally thought Rob was going to die,” says the insider of the sole Kardashian brother, who gained over 100 lbs. and had avoided the public for nearly three years. “They feel like Chyna saved him.”

Adds the insider: “The [Kardashian sisters] have gotten over their issues with Chyna now. They’ve welcomed her in.”