Actor Michael J. Fox speaks out about some of the lessons he's learned since revealing he had Parkinson's a decade ago.

Fox has written a new memoir titled Always Looking Up and gives an exclusive preview in the April issue of Good Housekeeping, available on newsstands March 10.

The actor talks about how he was inspired by a famous athlete also struggling with a serious disease. "Then, Lance Armstrong showed up, and I started talking to him; I saw all these people with cancer who followed him to Paris for the Tour de France, and I saw the difference he was making in their lives. That put it together for me…having it be not so much about me, but [my being] a vehicle for it."

Fox speaks about how his wife, Tracy Pollan, and his four kids deal with with his illness. "If I am reaching for something, they will just do it and carry on. Again, people say to me 'How do you cope?' and I think, Cope?! It's really hard to even think that way. Sometimes I'll stop and think, Am I selling short the experience my family is having? But then I'll look back at it and say, no - they're having fun."

On a successful marriage, Fox has the following advice: "The secret to a good marriage, as far as I am concerned, is a joke I make: Keep the fights clean and the sex dirty. Tracy and I are taken aback sometimes when people come up to us and give me this sad moon face and then they give Tracy a hug, and say 'You are so strong.' We roll our eyes at each other, because we are having a really good time."