Critical to keeping long marriages alive is communication, Lynn said. "The minute communication stops, sex stops," she said. "And when sex stops, resentment starts."
She recommends "date nights" and not to talk about children or problems. "Hotel sex changes the environment," she said. "It doesn't matter if it's a Motel 6 or the Ritz Carlton. Get out of the house."
And remember that after 50, sex can be more than penetration. "Touching and teaching couples to slowly build to the next step and kissing, that's very important for the brain to kick in," she added.
As our bodies get older, many are on medications that can also affect desire and performance, drugs like antidepressants, statins and diabetes medications, Lynn said.
"Marriages operate very differently than they once did," she said. "Longevity, expectations, dual careers, changing locations, TV and computer. ... That process of renegotiation, if successful can produce a new marriage with the same person."
In the end, Kay and Arnold renew their vows on a beach: That was Kay's fantasy. And renegotiate, they do.
Kay promises to take an interest in golf and Arnold swears he will stop complaining, unless it's something "really worth complaining about."