"I was uncontrollably fragile over it, which I had never felt before, ever," the Grammy Award winner told the "Armchair Expert" podcast. "‘Cause I thought for once I was stable. I really believed that I’m safe. So that really devastated me I think more than any other instability I've ever felt,
Shania Twain shared that both she and her current husband Frédéric Thiébaud did not know their former spouses were having an affair with one another. (Dave J Hogan)
SHANIA TWAIN ON GETTING OVER CHEATING EX-HUSBAND MUTT LANGE: 'I JUST DON'T NEED HIM'
Actor Dax Shepard, host of "Armchair Expert," told Twain he was reluctant to ask about the affair.
Twain clarified that it isn't embarrassing for her. After the divorce from Lange, she married Thiébaud's ex-husband, Frédéric Thiébaud.
Although they spent time together as couple friends, Twain noted that her relationship with Frédéric did not materialize until after their respective marriages were over.
"I did not get close to Fred at all, we didn't have each other's numbers," Twain said. "He was not really part of our daily life because we're all working these crazy hours. A lot of travel [for his] very high-profile company, just suit and tie, and so he would be around, like — weekend dinners and stuff like that — we would all eat together and that was it."
Twain expanded that it was her ex-husband, Lange, who had more of a relationship with Frédéric.
Shania and her ex-husband Robert John "Mutt" Lange were married for 14 years. (Gareth Davies.)
"It would mostly be him and Mutt chatting, so I didn't really know Fred very well," she said. "I guess it was a beautiful surprise to then see how gracefully and graciously he was dealing with this — the same pain. He was so thoughtful about it all."
Shania Twain and Frédéric Thiébaud have been married since 2011. (Andreas Rentz/Getty Images for ZFF.)
"Oh god, how could I be so stupid," Twain recalled feeling after discovering her close friend and husband were in a relationship. "I was definitely mad."
At the time, the "That Don't Impress Me Much" singer says that she found some comfort in Frédéric also being oblivious to the situation.
"Neither of us saw it coming. . . . I allowed myself to trust too much, I can tell ya I'm being very honest . . . I did let my guard down too much."
"I was angry, though. The anger comes a lot from my childhood too, 'cause I'm thinking, 'Man, you can do anything to me, but if you f---ing lie, like, right to my f---ing face? Now, I'm so angry.' It wasn't just, 'Infidelity happens.' That was not me. Yah, I spun around in that for quite a while. That was the hardest part to let go of really — the anger, just like I'm f---ing mad about this."
Shania Twain is pictured here with friend Marie-Anne Thiébaud playing golf in Northern Ontario, Canada. (SplashNews.com.)
Twain, who shares son Eja with Lange, revealed that Lange and Marie-Anne are still together, although she does not speak to either of them.
Twain shared that she and Lange "parent well together," but that they "just text."
In hindsight, Twain's anger with Lange has dissipated, allowing her to recognize what she does have.
"I think everyone gets what they deserve," she shared. "I got what I deserve, all right, I got the greatest man on the planet, and that's how I see it. So I'm not mad at myself anymore.