Christopher Wolfe, emeritus professor of Political Science at Marquette University, writes in the Public Discourse about the (past and future) threats to marriage:
It has been said that marriage has survived many social events, including the sexual revolution, and it will survive gay marriage too. I don’t think marriage survived the sexual revolution. Every war has winners and losers, and, as others have argued, the boys [or rather, the bad boys] won the sexual revolution (since it legitimized non-marital and recreational sex, gave them the option of deserting their wives for younger and better offerings, and even induced many women to adopt more male attitudes toward sex or accede to male demands in the sexual marketplace). The most prominent victims of the sexual revolution were the children who have been deprived of the enduring husband-and-wife family that should ordinarily be their birthright.
... But if it is true that heterosexuals have already damaged marriage as a social institution deeply, that still leaves the question of whether these wounds already inflicted on marriage justify the further infliction of additional wounds, in the form of legitimizing homosexual marriage, with its much more radical separation of marriage and children. The more sensible path, I think, would be to resist further erosion of the institution, and to undertake substantial efforts to re-constitute marriage as a stable institution in our society.