09/10/2012 12:27 pm ET

Brandi Glanville Denies Cheating With Her Ex-Husband Eddie Cibrian

Brandi Glanville is fuming over rumors that she's having an affair with her ex-husband, Eddie Cibrian, reports RadarOnline.

The "Real Housewives of Beverly Hills" cast member took to Twitter to deny allegations that an affair with Cibrian led his current wife, LeAnn Rimes, to check into a rehab center.

"I'm NOT cheating with. Y ex husband I would never do that #EWWWWWW," Glanville wrote on Twitter on Sept. 9.

Glanville married Cibrian in 2001 and had two sons together. But in 2009, after Cibrian hooked up with Rimes while filming the Lifetime movie "Northern Lights," the two engaged in a affair, cozying up at restaurants and meeting for trysts. Rimes and Cibrian tied the knot in April 2011.

Understandably, Glanville and Rimes have a bitter relationship, but Glanville appeared to offer sincere support when Rimes entered rehab in August.

"I totally support LeAnn's decision to enter rehab. My top priority is my children and at the end of the day we are a family. LeAnn is their stepmom, and they love her. I am wishing her all the best and I hope she will find what she is looking for while in rehab," Glanville said in a statement to Us Weekly.

Despite her message of support, rumors that she's cheating with Cibrian to get back at Rimes still persist. Last week it was reported that part of the reason Rimes checked into rehab was Cibrian's tendency to cheat.

"LeAnn has had major insecurity issues since she first got together with Eddie," a friend of the couple told Us Weekly. "She's been stressed about always being called a home-wrecker and also worried that Eddie is cheating on her. She's been on a downward spiral."

Rimes apparently has good reason to worry, since Cibrian has cheated before. Before his relationship with Rimes, Cibrian allegedly cheated on Glanville in 2006 with a cocktail waitress named Scheana Marie.

Rimes checked into rehab for "stress and anxiety" at the end of August, and left treatment to perform three days of concerts. According to RadarOnline, the singer is due back in treatment on Monday.

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