The 46-year-old "Make Me Like You" hitmaker, heaping praise on Shelton, said she feels blessed to have him in her life, reported Aceshowbiz.
"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," she said, referring to her marriage to 50-year-old Rossdale, who allegedly had an affair with their former nanny Mindy Mann.
"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," Stefani said of Shelton.
"I didn't have any kind of musical direction for this album. Every song was written around emotions. Of course (our relationship) was an influence."
Stefani's new work "This Is What the Truth Feels Like" is due out on Friday, March 18.