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Gwen Stefani is simply glowing, and her smile says it all.

Dressed in a head-turning gold dress over a pair of fishnet stockings, the "Misery" singer stuns on the cover of Cosmopolitan's September issue. In her interview with the magazine, she gets candid about her heartbreaking divorce from Gavin Rossdale, writing a song with her new boyfriend, Blake Shelton, and watching their romance come alive on "The Voice."

WATCH: Gwen Stefani Cuddles Up to Blake Shelton During Surprise Tour Appearance

Stefani, 46, and Rossdale, 50, announced they were calling it quits last August after nearly 13 years of marriage. Once their divorce went public, rumors started swirling that Rossdale was cheating on the rocker with their nanny, Mindy Mann. While neither of the two has specifically addressed these allegations publicly, Stefani says a few people in her close-knit circle know what really led to their split.

"Nobody except for my parents, the people involved, and whoever they told," she says of those in the loop. "Nobody would believe it if I could really say what happened. I went through months and months of torture."

WATCH: Gwen Stefani Talks Meeting Blake Shelton While in 'the Hell' of Her Life

While she keeps it cool when asked about the divorce during interviews, the platinum blond pop star admits she's left clues about her marriage troubles in her lyrics.

"All you have to do is listen to every single song I've ever written and it's all there," she explains. "It's an ongoing theme that I've had for a long time."

Following her split from Rossdale, it wasn't long before she was able to open her heart and find love again with Shelton. The two got to know each other while filming season nine of NBC's The Voice, and while their connection looked powerful on camera, Stefani admits their romance was a bit overplayed.

WATCH: Blake Shelton Says He's the Happiest He's Ever Been With Gwen Stefani

"[Blake and I] were laughing our heads off when we saw the blind auditions. I love NBC, but they for sure edited stuff to look like we were flirting," she tells Cosmopolitan. "They chose to run with that story before anything was even real. I hardly knew him. But it was like it was in the air -- happening before it happened."

At the time, Shelton, 40, was going through an eerily similar situation. He had called off his marriage to fellow country singer Miranda Lambert, just a few weeks before tapings for the hit singing competition show began.

"We were both having trust issues, as you would if you were us," Stefani reveals. "It was like, 'I have so many problems. How can I now be getting into another potentially huge problem? What am I doing?'"

And while she had never written a song with Rossdale (frontman of Bush) during their time together, Stefani says penning a track with Shelton came naturally. The two collaborated on "Go Ahead and Break My Heart," a catchy country tune that appears on Shelton's "If I'm Honest" album.

WATCH: Blake Shelton Calls Gwen Stefani His 'Hero,' Opens Up About Hitting 'Rock Bottom'

"Blake wrote the song and sent it to me," she explains. "He was like, 'Help me finish it.' I wrote a verse and sent it to him, but he was gone because he doesn't live in L.A. He didn't have Wi-Fi, so he wasn't answering me back! As soon as he came back to town, he brought his guitar over. We were like, 'We wrote a song together! This is crazy!'"