Adrienne Maloof and Paul Nassif separate: Is 'The Real Housewives of Beverly Hills' to blame?

Fans of Bravo's "The Real Housewives of Beverly Hills" have watched Adrienne Maloof and her husband of 10 years, Paul Nassif, bicker for the past two seasons, but according to one source, the couple have been on the verge of breaking up for awhile.

"The show was the killer. It was the straw that broke the camel's back," a source tells People. "It's not a surprise at all. They've been on the cusp of splitting for a long time."

Nassif filed for legal separation on Monday (July 30), citing irreconcilable differences. The couple have three children together -- 9-year-old Gavin and 6-year-old twins Christian and Colin. According to the filing in Los Angeles Superior Court, Nassif is seeking joint physical and legal custody, and according to TMZ, reports of a brewing custody battle are totally false.

"Dr. Nassif's sole focus is making sure both Adrienne and the kids are as happy as possible in this very difficult time," a source tells TMZ. "His goal is to ensure the best interest of the children."

Another thing that likely won't be a battle is the couple's division of assets thanks to a prenup. TMZ also reports that Nassif does not want the details of the split to be a plot line on "The Real Housewives."