Gay spouses have none of our guilt about sex-before-marriage. They have no tedious obligations towards in-laws, need never worry about Oedipus or Electra, won't have to face a menacing set of brothers or aunts should they betray their spouse. But without these obligations--why marry? Gay marriage is as good as no marriage at all.
Not only is it blatantly obvious that Mr. Shulman has never met a gay couple, but it should be pointed out that he has been married three times. Guess he doesn't know so much about "traditional" marriage either.
As it is quite likely that Sam picks and chooses his citations from the Bible, maybe he ought to realize that divorce is a "sin":
And I say to you, whoever divorces his wife, except for immorality, and marries another woman commits adultery