Crime Crime History Luann D'Agostino Addressed Tom's Cheating 3 Weeks Before Divorce: 'I'd Kill Him First & Then I'd Leave' Luann D'Agostino opened up about Tom D'Agostino's alleged infidelities three weeks before they split, saying on the Real Housewives of New York City reunion that she'd "definitely leave" him if they were true By Dave Quinn Dave Quinn Dave Quinn is a Senior Editor for PEOPLE. He has been working at the brand since 2016, and is the author of the No. 1 New York Times best-selling book, Not All Diamonds and Rosé: The Inside Story of the Real Housewives from the People Who Lived It. People Editorial Guidelines Published on August 16, 2017 10:00AM EDT Before Luann D’Agostino announced that she and husband Tom D’Agostino were divorcing after only 7 months of marriage, the Real Housewives of New York City opened up to her cast mates and to host Andy Cohen about what, if anything, would cause her to leave him. On the RHONY reunion part 1, which was filmed three weeks before the couple officially split, the 52-year-old former countess was once again faced with rumors of Tom’s infidelities from her fellow New York City Housewives — this time allegedly taking place after the couple had said their “I dos.” Of course, Luann has a lot of experience knocking down these sorts of claims, having spent two seasons on the hit Bravo show defending their whirlwind romance. But on the reunion, Luann showed a more vulnerable side — admitting that it alarms her to hear the constant rumors. Asked what she would do if those claims ended up having validity, Luann gave a swift answer. “I would definitely leave,” she said in a clip of the reunion released Wednesday morning. “I would. After I kill him. I’d kill him first and then I’d leave. You can push me so far but once you push me over the line…” Bravo Said allegations appeared to be true only once, when Tom, 50, was caught by a friend of costar Bethenny Frankel’s kissing a mysterious blonde at The Regency Hotel the day before their engagement party. Luann forgave her then-finacé and has maintained he’s been faithful since their lavish New Years Eve ceremony in Palm Beach — despite his flirtatious personality and “hot mic” moments on the show (including a scene in which he referred to himself as a “dog with a collar” while chatting with an ex at a party). “I admit his humor is a little off,” Luann said on the reunion, indicating that she understood how Tom — who was a lifelong bachelor before they wed — came off on the show. Robin Marchant/Getty The reality star also revealed that she did not have an open relationship with Tom, telling Cohen, “I’m not interesting in an open relationship otherwise I wouldn’t be married.” Her comments may not have convinced her RHONY costars. “You stayed with Alex all those years,” Sonja Morgan said of Luann’s first husband Count Alexandre de Lesseps, whom Luann had previously said cheated on her. “Well, that was different,” said Luann. “You see we were separated and I didn’t really want anyone to know.” FROM PEN: Highlights from Luann de Lesseps & Tom D’Agostino Jr.’s Wedding Luann announced on Twitter Aug. 3 that she and Tom were divorcing. “It’s with great sadness that Tom & I agreed to divorce,” she wrote. “We care for each other very much, hope you respect our privacy during this sad time!” Days later, she denied allegations that Tom had been unfaithful. “I do not think Tom cheated on me, definitely not,” Luann told Page Sixon Aug. 3 when asked the reasons for their divorce. “God knows he’s got himself in some trouble in the past, but I don’t believe that continued [while we were married].” ”It was impossible, we were having problems and we tried really hard to fix things, and we finally came to the conclusion it was just not going to work,” she continued. “It was a tough decision and we are both very sad about it. But the truth is we just weren’t getting along.” Part 1 of The Real Housewives of New York City airs Wednesday at 9 p.m. ET on Bravo.