How Shania Twain 'Swapped' Husbands With Her Ex-Best Friend After Devastating Affair

Shania Twain's love life took an unbelievable turn when she ended up marrying the the ex-husband of her ex-husband's mistress.

The singer, now 56, endured public humiliation in 2008 when it was revealed that her then husband, Robert Lange, was cheating with her secretary and best friend, Marie-Anne Thiébaud. Watch the trailer for a new documentary about the affair below:

This marked an incredibly difficult time in the country singer's life as Eja D'Angelo, the then-couple's daughter, was only six at the time.

The had married in 1993 after meeting in Nashville where he offered to produce Shania's next album and write songs for her.

While it's not known if Marie-Anne and Robert stayed together, Shania, incredibly, went on to get engaged to Marie-Anne's ex-husband Frédéric, a businessman, in 2009.

Her divorce from Robert was finalised in 2010.

Shania explained that the failure of her marriage and that of Frédéric's caused the pair to bond and eventually fall in love.

The singer opened up about the split to Ellen DeGeneres, as reported by the Huffington Post, and said: "It was a very difficult time emotionally for both of us.

"I would say that he was probably stronger through it than I was."

"He was a tremendous support; we were a support to each other and really found something beautiful in the end and unexpected."

The pair's unexpected happy ending became known in 2009 when they were seen wearing wedding rings, however, Shania's manager didn't confirm that they were engaged until the following year.

They went on to tie the knot in 2011 and have been happily married ever since.

While the singer does co-parent with her ex-husband, she has nothing to do with her ex-best friend.

"I don't invite that trigger into my life," she said of Marie-Anne. "She's not my future. She's my past."

Infidelity is a painful thing for anyone to deal with, especially in a marriage where there are children involved, but the singer explained that it ultimately taught her that she could survive anything.

"Survival is everything. I was in quicksand. I panicked, like everybody does, but I didnt surrender. I found a way out," she said.

"Sometimes I get overwhelmed coping with things, but experience also teaches you how to manage. When you get older, you have so much experience at falling and getting up. You're not going to stop falling. But you will get better at getting up and brushing yourself off. I believe that. I've lived it."

The unbelievable story is set to be revealed in more detail in the new Netflix documentary Not Just A Girl.