Look Out, Ramona! Estranged Husband Mario's Mistress Resurfaces In New York City Days Before Singer's Tell-All Release

Watch your back, Ramona Singer!

The sassy 58-year-old is celebrating the release of her juicy tell-all, Life On The Ramona Coaster, this week in her hometown, New York City— but her nemesis has returned to the city that never sleeps.

RadarOnline.com can exclusively reveal that the woman who broke up The Real Housewives of New York star's marriage, Kasey Dexter, 32, was spotted at West Village restaurant Perry St on July 24.

Sources say the fitness instructor relocated to Florida last year following her tumultuous affair with Ramona's estranged husband, Mario, 60.

As RadarOnline.com reported, the Bravo star was devastated by Mario's betrayal with the much younger Dexter, which led her to announce her plans to divorce last August.

In her memoir, Ramona says she contemplated suicide and popped anxiety pills amid Mario's cheating.

"The stress of everything became unmanageable and it began to wreak havoc on my mind, body and spirit," she writes. "There were times when I was so low that I almost felt like throwing myself in front of a subway train."