The Real Housewives of New York City star filed for divorce this week from her husband of 27 years, PEOPLE has confirmed.
This follows reports that she had caught him with his girlfriend at the couple's Hamptons home last weekend.
Ramona has not publicly confirmed that she and Mario are separating, and on Wednesday called the situation "a personal and private matter for our family" and asked for "privacy during this difficult time."
But a source told PEOPLE this week that Ramona called the police on Mario after catching him last weekend. And former Housewife Jill Zarin told PEOPLE: "Ramona has been protecting him. She looked the other way when people told her he was cheating."
Season 6 of The Real Housewives of New York City premieres March 11 on Bravo.
Reporting by LIZ McNEIL