"Kelsey is being insensitive to our children," Camille, 42, tells Radar Online.
The reality star's friend, medium Alison DuBois -- who famously clashed with Kyle Richards during the show's first season -- says Camille is perfectly capable of raising daughter Mason, 9, and son Jude, 6.
"Camille is an excellent mother, and Kelsey truly doesn't have a leg to stand on," DuBois says. "Good luck with that battle, Kelsey -- you are going to need it."
Kelsey's rep declined to comment, saying only that "any statement would be inappropriate. The filing speaks for itself."
After 13 years of marriage, the couple's divorce was finalized on February 10; Kelsey wed Kayte Walsh 16 days later in NYC.