Since her husband was diagnosed with Parkinson's 18 years ago, Tracy says their marriage has changed…in a good way. "When we were first married, he was so busy working all the time," she says. "So, in some ways, it's made him a lot more available."

Even when he's symptomatic, Michael says his wife sees past the shaking and physical challenges. "She sees who I am, and she likes me as much as she ever liked me," he says. "We have a sense of humor about life, and we enjoy life. We feel every day that we're so blessed."