That is, after all, the primary purpose of marriage; while not every marriage is required to seek that goal, I think one of the major reasons for the decay of families in this country is that people are losing sight of what marriage is really about. To accept 'same sex marriages' is to abandon any and all concept of why marriage exists in the first place.
You're right, of course. I think selfishness has a lot to do with it. As Dr. Keyes says, a selfish, hedonistic approach to relationships is incompatible with marriage.