"If he goes to a bar with his friends, a tabloid is going to report about it. Same goes for me. Trust is what it is," the singer tells Redbook magazine.
“Either you trust someone or you don’t. And I’ve never trusted anyone more than I trust Mike,” she says.
"You know how you feel when you get full? Well, I don't get full," she says. "I can eat a lot. Mike and I were in Italy for 10 days and I put on 8 pounds. So in real life, I have to make sure I'm not eating just to eat."
The Grammy winner, who's starring in NBC's live production of The Sound of Music on Dec. 5, admits that she was prompted to slim down after winning American Idol in 2005.
"I put on a lot of weight [during the show] because we were locked in a room all day with a craft service table. I was bored, so I was just eating," she says. "I was never overweight, but I feel better with myself now."