Conservatives nation-wide have launched a campaign to "save marriage." While a few writers at National Review have proposed making it harder to get a divorce, that is not the goal of the campaign to "save marriage." The actual goal of the campaign is to make it harder to get married, at least in one case. The campaign to save marriage is motivated by the fear that Hawaii is on the verge of legalizing same-sex marriage.
The Hawaii Supreme Court has issued an advisory decision that suggests that prohibition of same-sex marriage violates some section of the Hawaii Constitution. The Court decision did not institute same-sex marriage in Hawaii, but it has opened the door.
Article IV, Section 1 of the U.S. Constitution requires that "Full Faith and Credit shall be given in each State to the public Acts, Records and judicial Proceedings of every other State." If Hawaii legalizes same-sex marriage, then such marriages entered into in Hawaii would have to be recognized in the other states.
Christian conservatives are worried that recognition of same-sex marriages will render their own marriage vows meaningless. Some conservatives have not waited. Ronald Reagan, Newt Gingrich and Rush Limbaugh have all divorced their first wives, and in the case of Rush, more than one. In California, many marriages end in divorce; if same-sex marriage is legalized here, it may lead to more divorce because same-sex couples who marry might get divorced. But it is hard to see a direct impact on heterosexual marriages.
Society has an interest in promoting monogamy. Prevention of sexually-transmitted diseases is one reason to promote monogamy.
Stable monogamous relationships are important factors in saving, acquisition of property, and personal economic growth. Stable long-term relationships also contribute to health and longevity.
If same-sex marriage is unacceptable to the conservatives for symbolic reasons, then a good compromise would be recognition of domestic partnership agreements, for homosexuals, and for heterosexuals who are not ready for marriage.
Heterosexuals who are secure in their identity have no reason to fear homosexual monogamy, and many reasons to applaud it.