The Couples

He: "The cell phone was created for him," Karen said.

She: Classic introvert. Nonverbal in the morning and right after work.

What he's learned: She's not rejecting him when she's quiet. That's who she is. When she goes solo camping with their dog, he's learned to say: "Have fun!"

What she's learned: "For Pat, human interaction is like breathing. When I need someone to talk to, he is always there for me."

Secret of their success: Focus on their common interests; kids, coffee, travel, skiing, running, camping, films. "There is more to bind us than divide us," Karen said.

What he loves: "She encourages me to socialize more. I find myself enjoying situations I wouldn't have expected."

What she loves: "His sense of humor, keen insights."

For her: "Together, we do more things than he used to do, but less than I did. My social network has gotten smaller as I spend more time at home."

How they succeed: "We don't try to change each other." He's working to stretch his comfort zone without overextending. She tries to meet her social needs in ways that may not include him.

Who's the introvert? Hint: They'd often "bump into each other at the printer" at work where she accused him of "fondling" her printouts. He'd turn red and stumble away. She finally asked him out for a drink.

She: Eighth of nine siblings. He: Older of two.

Biggest challenge: She'll engage anyone in a conversation.