Opposites may attract, but that's not the case for Gwyneth Paltrow
and hubby Chris Martin
Although they have separate careers – she is an Oscar-winning actress, turning 40 on Sept. 27
, and he is the Grammy-winning Coldplay frontman, 35 – their common interests outside of work keep their bond strong, Paltrow tells her close pal, designer Diane von Furstenberg, in InStyle's October cover story
"We laugh a lot, and at the same jokes," says Paltrow. "We like the same music and we like to do the same things."
But having so much in common can also have its drawbacks.
"Our artistic temperaments together [is the hardest part]," Paltrow says. "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."
The pair, married since 2003
, have two children together
– daughter Apple, 8, and son, Moses, 6 – and they're not necessarily opposed to having more.
"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,' " Paltrow says. "But a part of me would love to have another. Of course, I'm old now!"
See Gwyneth's best red carpet looks on InStyle.com
Try on Gwyneth's hairstyles