Shania Twain on 'Today': 'My friend was now a backstabber, my husband was now my backstabber's new love interest'

shania-twain-from-this-moment-on-book-cover.jpg Shania Twain is promoting her new book, "From This Moment On," in which she writes about her life growing up in poverty, in a home in which her stepdad abused her mother and the break-up of her marriage when her then-husband allegedly had an affair with her then-best-friend.

She tells Meredith Vieira on "Today" that her childhood made her "feel very insecure, it as a very unstable environment." "I think it just keeps you on your toes and worried ... that's why I had to write a book. I felt I needed to unravel this life of so many extremes," says Twain.

"I am genuinely a very private person and I've probably been just too closed and up to now probably more closed than what was good for me. I also feel that a lot of that was just a bit of fear and anxiety and worried about what people would think all the time," she continues. "Now I'm at a point where I feel sharing and giving testimony to a lot of things I've experienced in life will do more good for others than it would do keeping it to myself. It also forces me a bit out of my comfort zone."

Meredith reads a passage from the book about the affair between her husband and friend. Twain writes, "My friend was now a backstabber, my husband was now my backstabber's new love interest. They were open about their intolerance of my grief and impatient for me to get over it already, but change wasn't instant or final. Like any death it would take time."

Shania says of that passage and that part of her life, "That was embarrassing for me. I've been thrown into the public eye with something I'm very uncomfortable with. But I think it's time to face a lot of things that are uncomfortable head on and get them over with and that just makes it easier to move on on many many levels."

"I started writing and obsessing about the break-up of my marriage. I just couldn't get past it. When grief carries on too long, into the second year, for example, you have to start looking a little bit at getting help," she says.

"From This Moment On" is in bookstores and available for download now. You can read an excerpt at the 'Today' website.

Photo/Video credit: Atria