Dean McDermott was sitting besides his wife at the time so she jokingly asked him who'd been with in Toronto the previous weekend? "There wasn't an ounce of me that thought it was real," she said. "I trusted him."
Tori and her husband talk about the painful moment she found out about his liaison
Another call from her rep confirmed that the Hollywood mum's worst nightmare had come true and that the girl involved was willing to be named.
Despite the terrible news, Tori went ahead with plans to watch two of her children perform in their Christmas show. Her other two youngsters were on her lap, with Dean by her side. "I was so proud and devastated all at the same time," she said, recalling her feelings at that moment.
The couple - who are parents to Liam, six, Stella, five, Hattie, two, and 17-month-old Finn - have been lifting the lid on the problems in their eight-year marriage for Tori's new reality show True Tori, aired by Lifetime channel.
In it the mother of four is also seen driving to visit 47-year-old Dean at the rehab centre he himself checked into to deal with his "alcoholism and addiction and depression and mental health".
The mother of four is finding it difficult to cope with the children on her own
Chased by paparazzi, 40-year-old Tori admits on camera that she is "excited" to see him again.
"I feel like that's the wrong thing to say. I feel like it makes me sound weak," she adds. "But it's been really hard and I miss him. I miss having my best friend. I miss having that support, that person that's your go-to in life. And that was just stripped from me. I had it for seven years and it was just gone one day."
Later she is seen touching up her make up to look good for Dean. Addressing the viewers, she pleads: "Don't judge me".
During their emotional therapy session at the centre, Dean begs to be allowed home but Tori refuses, giving the reason that it's the only hold she has over him.
The family a month before the revelations
The cameras also followed the beleaguered mum as she struggled with looking after her children on her own. Tori revealed that she spent Christmas alone because of her husband's treatment and that the last time she was on time with the school run in the morning was December when he was home.
"I don't do a great job [alone]," she admitted. "But at least they're fed and alive every day!"