The Breakdown of Traditional Relationships and Marriage.

In order to have healthy, functional adults who will have healthy, functional marriages, there have to be healthy, functional kids, first.

Most people today can't even live decently with family never mind strangers. The extended-family situation would be untenable for much of our culture at this point. That makes things which are really desperately needed -- such as small scale communal living (particularly for people without families) -- fairly unworkable.

I think you could compare the relationship dissolve element with job dissolves as well -- our culture to a great degree has dissolved period. Marriage issues are really only one of several reas where it is evident. I see this as more of a secondary effect of cultural degradation (the dissolution of extended family, let alone family, is a great deal of what I see as source of that) than the primary cause.