“When marrying, ask yourself this question: Do you believe that you will be able to converse well with this person into your old age? Everything else in marriage is transitory.” ~Friedrich Nietzsche Last month, Doug and I celebrated our 42nd anniversary. During a celebratory dinner at a local restaurant, our server asked us if we’d share the secrets of a long and happy partnership. She was living with her boyfriend, she said, and wasn’t sure about their future together. Doug and I assured her that the success of a marriage depends on the couple — and every couple is different, of course. For us, shared values and interests are essential,…