In my training as a Marriage and Family Therapist, I was taught that married couples tend to do better when they share a cause that they perceive to be bigger than themselves.  Although this idea was presented as modern research, it is a godly principle that the Church has understood for centuries.  What Aristotle knew in his day simply reflects the fundamental human design to find fulfillment not in other humans, but in God.  In this video, Father Barron does a nice job of articulating this idea.