While it was never an easy topic for Ramona Singer to discuss openly, the Real Housewives of New York star is revealing details about her split from Mario in her memoir, Life on the Ramona Coaster. The book is slated to hit retailers (like Amazon) on July 28, and the Daily Dish is sharing excerpts before its release date. (You can read another passage, where Ramona recalls her relationship with her abusive father here.)

In a second excerpt, Ramona opens up about confronting Mario when she suspected he was having an affair. Check it out below.

All that summer and into the fall, I was working nonstop. I remember the night of the cast party after we wrapped filming for Season 6, I wanted Mario to come with me like he always had at the end of every other season, but he said he was going to Westchester with a friend instead and didn’t come home until after midnight. What can you do in Westchester after midnight? If I questioned where he was, I felt he would get defensive and snap at me. At that point I felt his behavior had become unacceptable so I decided to go to our Southampton house by myself for the weekend to get some space. When I came home, I remember Mario told me he thought he needed to move out for a while. For the first time I considered the possibility that there might be another woman and I asked him straight out if there was. He told me no and I believed him. After that, he gave me a letter in which he explained how unhappy he had been. I tried to understand where this was coming from because I felt that we had been happy all summer. I remember his response was that it was because he was a good actor. I told him that we owed it to our marriage to go to counseling, so we started going to therapy together and I was hopeful that we would figure out a way to resolve our issues. That October, I remember walking along Park Avenue with one of my good friends, before going to therapy one day, and she said to me, “I hate to be the one to tell you this, but I think you need to know,” she paused and then said slowly, “I think Mario has been seeing another woman.” “What are you talking about?” I said, in complete denial.“Well, you know the other night when we were at Plaza Athénée for that party. People overheard him arguing with a woman on his cell phone when he was in the men’s room. He was screaming at her.”

I was stunned. I remembered that Mario had gone off that night to make a phone call and I had to admit that I did think he was gone for a little too long. I had also thought it was strange that he had wanted to meet me at the party since Mario hates arriving at events on his own. That eve-ning we went to therapy and I decided to bring up what my friend had told me. Although I felt as if we had been making progress and I didn’t want him to think I didn’t trust him, I couldn’t get what she had told me out of my head. I asked him if he had been fighting on the phone with a woman at the Plaza Athénée party, but I felt like he just brushed me off and made a joke of it so I decided to drop the subject.At home, later that same night, I walked into the den and I saw that Mario was talking on the phone. I remember as soon as I walked into the room he got very stiff. “Alan, let me go now. Ramona just walked in,” he said abruptly and ended the call.Alan is a good friend, so I said, “Mario, why did you hang up? I would have said hello to Alan.”“This was a different Alan. You don’t know him,” he answered. I sat down beside Mario. He seemed to be getting agitated. He asked me why I had come into the room, but I couldn’t remember. My mind was blank. Then something in my brain just snapped. It was like a veil had been lifted and it dawned on me that he had not been talking on the phone to a different Alan, or to any man for that matter. I stood up and I looked at him. “Mario, that wasn’t a different Alan on the phone, was it? You were talking to a girl just now, weren’t you?” I remember his face looked like he had seen a ghost. His eyes went wide. His mouth fell open. He had that same expression on his face when I was pregnant with Avery and I told him that my water broke and we had to go the hospital. He looked like a deer in headlights.“Just admit you were talking to a girl. Just admit it,” I shouted.He snapped out of it and got defensive, “Yes, I was. Do you want to know what else I do with her besides talk?”

If you want more Ramona, check out the most ramotional rides on the Ramona Coaster, below.