The 39-year-old, who is married to Martin since 2003, said it is really a challenge to have same interest when both of them are in same field, reported Showbiz spy.
"We laugh a lot, and at the same jokes. We like the same music and we like to do the same things. Our artistic temperaments together (is the hardest part).
"Artists are sensitive. There are ups and downs, mood-wise. Musicians need a certain gravitas and focus in order to write. The temperament that goes with someone who is creative can be challenging," she said.
The couple, who raises two kids with Martin, said she wanted to have more children.
"My brain says, 'Oh, I think I'm done, the kids are so big now, and I don't want to go back to changing diapers. But a part of me would love to have another. Of course, I'm old now!"