There is a strange denial of reality regarding the arguments being put forward against gay marriage. Prior to this issue going through the courts and the current controversy people of the same sex were getting "married." They were taking oaths to stay with each other and be faithful to each other for the rest of their lives. More than that, many were taking these oaths in churches before the eyes of their God(s). Within their religions their marriages were in fact sacred. Clearly under the First Amendment the government cannot say these marriages are not religiously sacred.
The relationships exist, the oaths exist, the emotions exist. They are families, raise children in many instances and also split up upon occasion. The only issue is whether their is same sex marriage, the issue is only whether the state will acknowledge these relationships. While I personally think that the claim that people of the same sex getting married somehow harms marriage is completely unfounded, the relationships are already in place, the mythical harm has been done.
As I said before here nothing happened when Vermont began legally recognizing civil unions. The family structure has been ratified, the only problem is the separate but unequal status under the law of civil unions.