When I met them, Bill and Janet Ligon were living in a sunny, plant-filled home in Ashland, Oregon. Born in Malaysia of English parents, Janet was just turning 85, and Bill, who grew up in Tulsa, Oklahoma, was turning 90. They told me they had been happily married for over 60 years. Bill used a cane for balance. Because of an ankle injury he sustained while serving in the Army, he could no longer ski or square-dance. If he stood for too long, he got tired, he said. He’d also had a heart valve replacement, an operation Janet also needed. But both Bill and Janet agreed that they were enjoying the twilight of their lives to the fullest, despite the health challenges. The love they felt for each other was palpable. They held hands while we talked, kidded each other, and finished one another’s sentences. One of the reasons they …