Cameron & Nicole THERAPY SAVED OUR MARRIAGES

On the advice of sister-in-law Nicole Richie, Cameron Diaz keeps her union with Benji Madden healthy via counseling!

Cameron Diaz only has one way to describe her marriage to Benji Madden. "It was the best thing that ever happened to me," she told brother-in-law Joel Madden who is her husband's twin during the Dec. 10 episode of his Artist Friendly podcast.

And the Bad Teacher star, 52, got candid about what keeps their nearly 10-year union running smoothly.

"Therapy is a big thing in our family, thank God," said Cam. "It's what we depend on, so you have that commitment to work on it." Joel, 45, was quick to add that he and wife Nicole Richie, 43, are also devoted to counseling.

Twin Track
"Joel and Benji love that their wives are so close," says an insider. "But sometimes the guys joke they are left completely out of the loop on certain family matters!"