Ramona Singer 'Miserable' Over Mario's New Bachelor Lifestyle — 'Different Girl Every Week!'

Ramona Singer filed for divorce from cheating husband Mario more than a year ago. But as the proceedings continue to drag on, RadarOnline.com has learned, the Real Housewives of New York City star's estranged husband is living it up as an eligible NYC bachelor, while she's totally miserable!

Mario, 60, "has become a fixture on the nightlife scene in New York City, with a different young woman on his arm almost every week," an insider said. "Mario is happily single, and intends to continue dating as many hot chicks as possible. He says it's the happiest he's ever been!"

"Meanwhile, the fact that Ramona is miserable doesn't bother Mario in the least," the source continued. "He was unhappy for years living with her, and is vowing to never be tied down again."

Ramona, 57, announced her plans to divorce Mario last August after she allegedly caught him cheating again with personal trainer Kasey Dexter, 32. She had filed in January, but attempted to save her marriage unsuccessfully over the next few months.

Since then, Mario has been on several dates with Ramona's fellow Bravo reality star Chantelle Fraser, who will join the upcoming season of Blood Sweat And Heels.

Mario also joined the popular dating website, Match.com, as RadarOnline.com reported.

Previews of the upcoming season of the RHONY feature Ramona and Bethenny Frankel shedding tears and commiserating about their divorces.

The Pinot Grigio loving gal has been "humiliated and embarrassed by Mario's actions," the source explained. "It was bad enough Mario cheated on her publicly, but living with the aftermath has been even worse."