Gwen Stefani thinks "it's a miracle" she and Gavin Rossdale are still together.

Gwen Stefani and Gavin Rossdale

Gwen Stefani and Gavin Rossdale

The 'Baby Don't Lie' hitmaker, who has three sons, Kingston, eight, Zuma, six and 11-month-old Apollo, with the British rocker, can't believe they have been married for 12 years and admits she initially thought he was out of her league.

The 45-year-old star said: "We go through so much together -- it's a miracle that we could stay together this long.

"I don't know if I was a nerd in high school, but I definitely wasn't the super-cute cheerleader so I never saw myself getting somebody like that. But I do think he's quite handsome. It's not the most important thing about him, but it is nice -- and he makes really cute babies!"

Gwen and the Bush frontman, 49, both have busy careers, but she believes spending time apart helps their relationship.

She explained: "[Gavin's] on a short tour right now, and he wrote me the sweetest note this morning. It's good to have those days when we both do our own things. I think that's what keeps relationships going, when both people can be themselves and have their own individuality. That's especially important for women. It's hard to find time for yourself."

Meanwhile, the 'Voice' USA mentor claims she is still surprised by her long-lasting success.

She told the March issue of Cosmopolitan magazine: "It still shocks me that people care about me. I trip out about it all the time. It's mind-blowing! For me, I've never gotten to a point where I felt, 'Okay, I've made it, I'm number one!' It's an amazing feeling to hit number one, but it's not that different a feeling from not being number one. It's really about the journey -- that's where the joy comes. It's not about the end result, because there isn't really ever an end."