one never knows....
My marriage has lasted 18 years and my wife and I both consider ourselves lucky. We have had rough times as does every relationship. We have both worked hard at making our relationship work. Communication; respect for each others privacy and perspectives; and just being friends. But both parties have to work at it.
My parents were married 60 years ( to each other) and their relationship , by all outward appearences, was just like an episode out of "Ozzie & Harriet". They were the sweet couple you saw waltz like "Fred Astair and Ginger Rogers" across the dance floor; smiling; and holding hands walking down the park lane.
At the time of my fathers passing last year; it came to my attention ( very dramatically at his hospital bed) that my father had a girlfriend; and my mother was aware of it; and "tolerated" it. It was further shocking to me to learn that several years ago my mother had taken a boyfriend. ( my father also knew; and was not so happy; but also tolerated it). Mind you this all happened after our departure from the JWs. ( At least that I know of )
I was in a mild state of shock discussing this with my wife . We took it in stride. Who am I to question my parents relationship? It lasted for 60 years and I have no doubt they loved each other and myself and siblings? who am I to question or criticize their choices for their relationship? Or what is required for the dynamics of their relationship? It was worked long before I came onto the scene.
to the topic; whatever works for two people---it may vary from one relationship to another. Based on my experience to date---Communication is the key; honesty and commitment. The rest are details.