The 30-year-old, who has has been married to Fisher since 2010, said she wants to be a hot wife to her fit husband, reported People magazine.
"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!" said Underwood.
The singer also said she wouldn't hesitate to leave her career if it ever started to cause problems between her and Fisher.
"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.