The rise of long-distance marriage

THE Callahans, Karen and Kevin, got married in 1973 when they were college students in Des Moines, Iowa. Forty years, two children and umpteen moves across the country later, they put down roots. Karen took a job in Durham, North Carolina, while Kevin stayed in Parkville, Missouri, where he could be close to relatives and prepare their home for retirement. They see each other at least once a month, for birthdays, holidays and mini-breaks. They look forward to their phone calls, almost every night at around nine.