Their secret, she said, is giving each other freedom.
"You gotta trust who you're with and at the end of the day, right, I'm not here to be anybody's watcher. I'm not his watcher. He's a grown man," she told Howard Stern. "Will is a man of integrity so he's got all the freedom in the world. ... As long as Will can look himself in the mirror and be OK, I'm good."
Pinkett Smith, 43, called Smith, 46 "a gangster partner," and added she recognizes, especially in Hollywood, that he'll be attracted to other women. But she doesn't think he's going to run off with anyone else.
"Just because your man is attracted to another woman does not mean he doesn't love you. That's not what it means, and it doesn't mean he's gonna act on it," she said. "If your man can't really see another woman's beauty, how the hell is he gonna see yours?"
Unfortunately for her son, Jaden Smith, 16, some of his friends have noticed her beauty, she added with a laugh.
"It's so funny when your sons get to those teen years and they start coming to you... 'My friend is like, really kind of feeling you and it gets embarrassing when they talk to me about you,'" she said. "Jaden even still today is like, 'Mom...'"