Kris Jenner is "livid" after Bruce Jenner recently stepped out with her longtime friend Ronda Kamihira, sources tell Us Weekly in the new issue -- get the exclusive details here Credit: Stacie McChesney/NBC/NBCU Photo Bank via Getty Images; Axelle/Bauer-Griffin/FilmMagic

Better after Bruce? Not quite. Kris Jenner is "livid" after Bruce Jenner recently stepped out with her former assistant and friend of 20 years, Ronda Kamihira, sources tell Us Weekly in the new issue.

Making matters worse? A source tells Us that Kris, 58, is none too pleased to be fielding questions related to Bruce's burgeoning romance while promoting her new book, In the Kitchen With Kris. The mother of six, though, has been cautiously providing rather positive statements about her husband of 23 years, telling Ryan Seacrest on Oct. 21: "I hope he's doing his thing and having a good time."

The battle within is a different story. "She's livid and embarrassed," the same insider tells Us. "She told him she thought it was inappropriate."

On his birthday Tuesday, Oct. 28, Bruce received birthday wishes from Kardashian family members including stepdaughters Kim and Kourtney. Kris remained silent on Instagram, although she managed to extend birthday wishes on the social media platform to rapper Drake, of all people, on Oct. 25.

Despite Kris' outrage, another source says that Bruce, 65, plans to spend more time with Kamihira, 51 — whose kids once played with Kendall, 18, and Kylie, 17. "Bruce doesn't feel the need to explain his relationship with Ronda to Kris," explains the insider close to the former Olympian.

To counter Bruce's alleged betrayal, Kris has been keeping up on her own. Three weeks after Bruce stepped out with Kamihira, the momager went public with Corey Gamble, a tour manager for Justin Bieber, whom she met at Riccardo Tisci's birthday party in Ibiza, Spain, in August.

The momager even invited Gamble to Kim's 34th birthday party at Tao in Las Vegas this past Friday, Oct. 24. As one eyewitness recalled, "Kris and Corey were cuddling in the corner all night."

For more details on Bruce's newfound freedom and why he's lashing out now, pick up the new issue of Us Weekly.