By Julie K.L. Dam
Updated May 23, 2011 12:00 PM

Padding around barefoot in her brand-new beachfront home in the Bahamas, Shania Twain is trying to stay on top of her household: When’s her son Eja getting home from school? Which switch turns on that light? Where did her recently adopted puppy Jett just run off to? “It’s hard to keep up with everything,” the country star, 45, says with a sigh. “It’s been really crazy from all angles.”

Crazy? That’s nothing compared to the past three years of her life-a period during which, in short order, her husband of 14 years asked for a divorce; she found out he was allegedly having an affair with her best friend; and then, despite all her efforts to fight it, she ended up falling in love with the other woman’s ex-husband. “It is twisted,” she says of the double betrayal turned partner swap. “But it is very beautifully twisted.”

Whatever the circumstances, Twain is clearly relishing her second chance at love. She laughs easily when she’s around Frédéric Thiébaud, 40, the Swiss marketing consultant she wed on Jan. 1. She’s even open to having another child (“If it happened, it would be lovely, but it’s not a plan”). Most surprising of all, the famously private star is baring her soul in both her memoir, From This Moment On, and her docu-series on the Oprah Winfrey Network, Why Not? With Shania Twain. “My closest friends and family say they haven’t seen me this free-spirited and happy in years-many, many years,” she says. “And it’s definitely true.”

Of course, it took a lot of heartache to get to this place; Twain’s life has always been the stuff of a country song. From her humble beginnings in northern Ontario-she and her four siblings often went hungry and were devastated by their parents’ domestic violence and early deaths-Twain went on to become the biggest country-pop crossover star of the late ’90s. Hits such as “Man! I Feel Like a Woman”-produced by Robert “Mutt” Lange, whom she married in 1993-and the sexy videos that accompanied them fueled a career that earned her five Grammys and sold 76 million albums.

Yet at the height of her fame and fortune, she struggled with the relentless career demands and the lack of anonymity. “I just wanted to forget who Shania was for a while,” says Twain, whose given name is Eilleen. She took a break in 2004 and settled with Lange and their son Eja, now 9, in Switzerland-where she barely knew a soul-and “the isolation started to spiral,” she says. “I wasn’t expressing myself anymore.”

At the same time, she and Lange were growing apart. “It’s very hard to be honest with yourself when something’s just not working,” says Twain, who devoured self-help books. “Mutt had already made up his mind on what was going to be done, but I was in the dark.”

In March 2008 Lange told her he wanted a divorce. The next day Thiébaud broke the crushing news that he believed his wife, Marie-Anne-her best friend, to whom she had confided her marital problems-was having an affair with Lange. (Lange, 62, and Marie-Anne, 40, have denied the allegations.) The double betrayal sent Twain into a tailspin. “I was ready to die,” she writes in her book. For weeks she barely ate or slept. In one e-mail to Marie-Anne, she wrote, “I am dying, and I can’t take it anymore. This is killing me. Have mercy.” But she never got an explanation from her husband or her friend. “Some days the despair was so all consuming, I’d feel like it was coursing through my veins,” she writes. “I never considered harming myself, but I was harming myself-torturing myself, really, by trying to make sense of it all.”

Her only moments of peace were when she switched to mommy mode. “I had a son who needed me,” she says. “I didn’t always, but I kept it together for him when I needed to. Nothing else would have snapped me out of it.”

Twain reserves most of her ire for Marie-Anne; even now, she utters that name only once in the course of an interview. “I hated her,” she writes in the book. “I was disgusted that another woman’s lust for a lifestyle upgrade was worth the devastation of my family.”

The next year, when Twain read about tabloid reports that Tiger Woods‘s wife attacked him after finding out about his infidelity (the pair later denied it), she was relieved that she had already made peace with the situation. “I had been very angry, angry enough to lose control; none of us are above it. [Reading that then] would have been the worst example for me-that would have liberated me,” she says with a laugh. “‘Somebody get me my golf clubs! I’m goin’ over to her house!'”

In truth, the one time she did encounter the other woman, not long after the split, “I had a total panic attack,” she says. “I just told her that she was a bad person-that’s all I could get out! When I left her, I thought, ‘You’re such a wimp, you coward!’

That was my big moment, and I blew it!” Today Twain has no interaction with Marie-Anne and won’t allow her to have any contact with Eja either. “I just have no desire,” she says. “In fact my desire is to avoid her!”

The singer’s relationship with Mutt is more complicated. Their communication these days is “only about Eja, not about us at all,” she says, somewhat wistfully. “It would be nice to be friends and not just co-parents…I will always love him. You can’t just turn love on and off.” Not that she’s forgiven him and Marie-Anne, who, as far as she knows, are still together: “I will never be okay with what they did.”

Her anguish even manifested itself physically: After the betrayal she found herself unable to sing. Her show Why Not? follows her attempt to regain her voice after she is diagnosed with dysphonia, a squeezing of the voice box by the surrounding muscles-which she attributes to all the fear and stress she’s had in her life, not least of all her divorce. Still, she says, “I completely accept all of it, to the point of being able to say that things have turned out really well.”

Her relationship with Fred-despite her efforts to close herself off from romance-is proof of that, she says. “I really didn’t ever want to love again after the end of my marriage,” she says. “I decided I could live the rest of my life without love, but I was wrong. And I’m so glad I was wrong.”

Twain and Thiébaud, the two scorned spouses, started a friendship over their shared heartache. “What happened between us really came as a complete surprise,” he says. “We never, ever expected anything like this. It’s just really a beautiful love story.” Thiébaud was the first to express his love-and despite her growing feelings, Twain resisted. “There was quite a period when I thought pretty much the way everybody thinks about this relationship,” she says. ” ‘Oh, come on, this is a bit dangerous; you’re both grieving.'”

But little by little Thiébaud, who calls his wife Sunshine, won her over with his romantic surprises-from flying her to a Swiss glacier to renting out a movie theater for a dinner for two. “To express my love, words are not enough,” he says. “I’m more in love with her everyday.”

What finally opened her heart: the blessing of her son Eja and Thiébaud’s daughter Johanna, 10. “Children are so perceptive-they would have felt odd and didn’t,” says Twain. “We did! They didn’t! And we both thought, ‘If they’re okay with it, who cares what anybody else thinks?'”

That may well be Twain’s new motto. After surviving the darkest days of an already tumultuous life, she’s determined to write her own happy ending. “I don’t take any day for granted anymore,” she says. “Fred has given me a new lease on love.”