What will happen is that it will be forbidden to point out that same-sex "marriage" is wholly illegitimate and a mockery of the name. The end game of same-sex "marriage" advocates is to force acceptance and stifle any negative commentary on homosexual behavior. After the novelty of legalized same sex "marriage" wears off, very few homosexuals will bother to marry, but it will be ensconced in law that homosexual sex is just as good, natural and healthy as heterosexual sex.
Let's get serious and eliminate no-fault divorce. Then we'll see how much homosexuals really want to marry.