Beauvais, 53, discussed Rinna, 57, and Richards, 49, during Wednesday's episode of Watch What Happens Live after filming the RHOBH Season 10 reunion.
Beauvais said Rinna's involvement in the drama between Richards, her husband, Aaron Phypers, and Brandi Glanville was "too much" for her to handle.
"After the reunion, it was a lot for me," Beauvais said. "I just felt like she was... the stakes were too high for something that really is between Denise and her husband. It just seemed too much for me."
On Wednesday's episode of RHOBH, Richards denied she had sex with Glanville during a trip to Northern California in 2019. Rinna confirmed on Instagram Stories this month that Richards sent her co-stars a cease and desist letter over the affair drama.
On WWHL, Beauvais said she didn't believe Glanville's claim that she had sex with Richards.
"I didn't believe it. For me, I thought consider the source. If it had been somebody else that was a little more credible I would have been like, 'Okay, maybe.'"
On Wednesday's episode of RHOBH, Richards also denied insulting her co-stars Teddi Mellencamp and Erika Girardi. Beauvais said she does believe Richards made the unflattering remarks.
Richards said on WWHL in May that her friendship with Rinna has changed since their RHOBH drama.
"There's definitely been a change in our friendship. You know, people will see that as the show plays out," Richards said. "We've been friends, though, for over 20 years and we never know what's going to happen in life. So, we'll see."