Who is David from Out on a Limb and what is their importance?

David is Shirley's good friend. Once David lives life in the fast lane with a high paying job, fast cars, and many women. However, David meets a woman named Mayan in the mountains of Peru and learns about spirituality and extraterrestrials, a knowledge that changes his life. David stops living his life in the fast lane and instead begins traveling the world, expanding his spiritual beliefs, until he finds a friend in Shirley MacLaine.