Carrie Underwood has a simple motivation to keep in shape -- her husband Mike Fisher's killer body.
She tells People, "Even when he's like, 'I'm so out of shape,' he still has a six-pack. Having Mike there –- I want to be a hot wife!"
Carrie takes her vows seriously and says if her career were to get in the way of her marriage, she'd give it up. "If Mike ever told me he needed me to quit, I'd quit. When you make that promise to somebody, and you stand before God and your family and friends, you've got to do everything that you possibly can to make that work."
Carrie is on the cover of this week's People magazine.