Benji Madden is Cameron Diaz's "rock"

A source told PEOPLE: "They talk things out, feel like friends, yet have a wonderful romance. They have grown together, and in some ways, he has been a rock for her. Benji is a good man, smart, deep and honest."

Cameron recently opened up about their marriage in a rare interview, calling Benji, 40, "the greatest human being".

She said: "I just want to build better, stronger friendships with the people who are in it with me. Of course, that includes my husband. Getting married to him was the best thing that ever happened to me. My husband's the best. He's the greatest human being, and he's my great partner. Marriage is certainly hard, and it's a lot of work. You need somebody who's willing to do the work with you, because there's no 60-40 in marriage. It's 50-50 period. All the time."

The 'Bad Teacher' star wasn't sure if she was "ready" for marriage when she tied the knot with the 40-year-old musician, but says she always knew Benji was "special".

She added: "I don't know if I was ready [when I got married], but I knew Benji was special. He's just a good man. There's no bulls**t. It's really refreshing. I'm grateful for him."

Cameron also admitted she's in no rush to return to the spotlight.

She said: "The way I look at it is that I've given more than half of my life to the public. I feel it's OK for me to take time for myself now and choose how I want to come [back] into the world. If I decide to.

"I don't miss performing. Right now I'm looking at the landscape of wellness and all that. But whatever I do, it has to be something I'm passionate about - something that just feels effortless."