Dressed in black slacks and a purple off-the-shoulder top with zebra stripe inset, Shania Twain stopped by 'Ellen' today. Though she's been very private in the past, the country star was transparent and open as she shared the pain of the betrayal of her divorce -- but at the same time, she said it all in that upbeat voice we remember well.

It was their secretary (and Twain's best friend) who had the affair with her ex-husband, "Mutt" Lange. The country star found out about the affair at Easter time from Frederic Thiebaud (her current husband of just over four months), who was then married to the woman caught cheating.

Thiebaud called her after their families had spent the Easter holiday together and said, "I've been waiting for a few weeks to tell you -- I've been hoping that they would tell you themselves. They obviously haven't, and I think you need to know." He told Twain that he had proof of the infidelity: hotel bills and things like that. Twain had a hard time believing it and revealed she was actually in denial, and she said it took months to deal with.

"Betrayal is really a devastating thing," Twain told Ellen DeGeneres. "The end of any marriage is very sad and it's devastating in itself, especially when there are children involved, but betrayal is a little bit ... that's harder to take. I struggled more with that." As for her divorce, the 'Any Man of Mine' singer revealed, "It took a long time to deal with, and it's a very slow grieving process on my end and on Fred's end, obviously."

Twain said, "I'm not angry when I talk about it anymore. I'm not even really confused because it's obvious that life just has to play out the way it's meant to, and how can I complain with the way it's ended up?" She added, "[The divorce] doesn't define who I am and it doesn't define my whole life. My whole life is a much bigger picture, and writing the book from the beginning gave perspective."

Her son is the reason Twain actually wrote her new book, 'From This Moment On,' so he would know the truth -- which also includes violent familial abuse she witnessed as a child behind closed doors. She hopes her speaking out will help others experiencing the same thing. She hopes her voice will help those suffering "in silence" as she was.

Twain did not go into the details of the affair in her book because it was just "not necessary." She explained, "I talk more about me and what I've learned from it really more than anything." Before the show ended, DeGeneres broke the news to Twain that she just made New York Times bestseller list with her new book.

As for the burning question on every one's mind, the talk show host asked Twain if she would ever sing again, to which the country star cheerfully responded, "Yes, I will sing again. Absolutely!"

Watch Shania Twain's Interview on 'Ellen'