Growing Up Sexual

Why would someone who's already traveled around the sun seventy times write an autobiography about his sex life?The possible answers are:1. Because he likes to write and was always obsessive about this subject.2. Because his story is unique.3. Because he thinks it has educational value lest we forget.4. Because if anybody is interested, he could use the money.5. Because the old dog can still bury a bone and reminiscing is a turn-on.6. Because that's how he found love.