marriage institution in America

What is happening to marriage as an institution in America. Mates of pretty long years of union say 40 to 50 are contemplating for split. Why? has the institution lost all its charm, or the candidates still maintain hopes for another trial and error even when they have crossed their ages productive level, say 60 and above. One has to scientifically examine the causes for such an ailment to the society. Is it an absence of a mentor, absence of moralistic and spiritual guides or reduced role of religion creating problems. When life becomes more self oriented caring little for others such things may occur. However, when people of repute like former Vice-president does it, the matter is more serious.