The 47-year-old television personality discussed her alleged affair with Richards during Wednesday's episode of Watch What Happens Live.
Glanville appeared in Seasons 2-6 of RHOBH and returned as a guest in Seasons 9-10. In Season 10, she claimed she slept with Richards, who is married to Aaron Phypers.
On WWHL, Glanville said it is unrealistic for Richards to keep certain aspects of her life private, given the nature of reality TV.
"I believe that's what she ultimately wants, but you're on a reality show. Everything that is your life will be shared. All of the skeletons will come out," Glanville said.
"You don't get to pick and choose what you want on the show. I'm sorry; you just don't," she added. "If you're gonna do a reality show, you have to share it all."
Glanville said she told people about the alleged affair because she is open about her life and was mad at Richards.
"My motivation is my off-camera life is the same as my on-camera life. So if I'm talking about it off-camera, I come on-camera, I'm talking about it on-camera. And I was a little bit pissed at her," she said.
Glanville insisted she was "more than friends" with Richards, who has denied the affair. Glanville said she and Richards hooked up twice, once at a bar and once on Richards' movie set in 2019.
"The first night I met Denise, we made out in the bathroom," she said. "Then she invited me away to her set, and we [expletive]. That was it."
RHOBH stars Teddi Mellencamp and Kyle Richards previously said on WWHL that Richards added "fuel to the fire" of the affair rumors by repeatedly bringing up Glanville during conflicts with the group.