“I was dead. I was literally dead, like panicking – like anyone would be,” she told USA Today. (Watch. People share the moment they knew their relationship was over. Post continues after video.)
The pair have three children together; Kingston, 9, Zuma, 7, and Apollo, 2.
Stefani then had to live out that shock in the public eye once news broke.
“Last February – I think a lot of people know my life fell apart – my family fell apart, everything fell apart. Together 20 [years]. You just crumble, you know?,” she said in an interview with NPR.
“I felt quite embarrassed. I was all the way down. And I just felt like, ‘God I gotta turn this around. I can’t go down like this’.”
It was then the 46 year old found support – and love – on the set of The Voice with fellow coach Blake Shelton.
The country singer had also recently gone through a public divorce from his wife of four years, Miranda Lambert.
"I think that when you go through what I went through, or what I’m still going through, you think you’re hopeless. You don’t know what’s going to happen. You panic," Stefani told Refinery 29.
"It was a really super-unexpected gift to find a friend, somebody who happened to be going through the exact same thing as me, literally mirroring my experience. I don’t think it’s an accident that that happened. It saved me."
As a way to cope, Stefani threw herself into music, channeling her frustrations of her separation from Rossdale and her new feelings for Shelton into a new album. While the response from fans to her personal songs have proved overwhelmingly positive, her record label wasn't always convinced. (Post continues after gallery.)