What's more, Olivia threw her parents an anniversary party on Real Housewives of New Jersey season 11.
The couple's daughter wanted to jump to her parents' defence, and penned a comment saying "this is my mommy [sic] and daddy and this is not true!"
Olivia then showed Jennifer the comment, telling her mother she was "defending you from all of these lies".
But Jennifer had to reveal to her daughter there was truth to the rumours. Bill had an affair with a pharmaceutical rep while Jennifer was pregnant with her fourth child Christian, the New York Post reports. Christian is now 10 years old.
"I sat her down and I kept my composure because I realised [my kids] will react to however I'm acting," she explained.
"I put on a brave face and said, 'Listen, Daddy did a bad thing. But that doesn't mean that he's a bad person. And when we love people, we forgive them when they make mistakes. And I've forgiven him and I'm okay.' She wasn't upset because I wasn't upset."
Later, Jennifer explained the situation to all of her five children including Justin, 17, Gabriella 14, and Jacob, 12.
She said Bill personally told Christian about his infidelity.
Her daughter Gabriella was "crushed", according to the reality star, whereas Justin was "irritated" and didn't want to talk about it again.
The affair was revealed in the premiere of season 12 of the RHONJ.
"I never told a soul. I didn't tell my parents, I didn't tell my cousins, I didn't tell my sister, I didn't tell my best friend," Jennifer added.