I agree that married guys on the downlow are a health menace to their wives and children. On the other hand, having known so very many GL's in the art industry in a major city, I do know several of both sexes who left all that behind and have stayed married to the same opposite-sex spouse for decades and are now grandparents, and no one has died of AIDS, so they must be making it work.
My point being that I do not believe that homosexual behavior is an absolute, inborn trait, as demonstrated by many of those who participate in it and leave it behind as they mature. Even the gay politicos try to make bisexuals pick a side, because it makes their rants so much easier.
Marriage is marriage, forsaking all others, even if a partner is bisexually functional: "all others" means "all others." It would seem that the fact of being bisexually capable creates an excuse for cheating in some people's minds; but it comes down to commitment to the marriage, yes or no. Continuing to same-sex cheat is still cheating, especially if it is contemptuously just using the opposite-sex spouse as a breeder. So if anything good can possibly come out of this gay marriage movement, it should be fewer downlow cheaters, since they would have the opportunity to marry one of their preferred people.
But if gays or bi's want children, bringing children into a SSM is an even worse fate for the child than having one parent on the downlow. I think that's why, religion aside, societies have not supported gay marriage anywhere in the world before the last few decades with the rise of global pharmaceutical advertising and lobbying having claimed that chemical birth control is 100% effective (which it is not) plus the clamor for abortion as a social benefit (which it is not). Homosexual and all non-marital sexual behavior by adult parents is statistically a greater threat to dependent children, period. Now, gay marriage is only being supported by ignoring the research, branding all objections as bigotry, and spinning an heroic-but-substantially-untrue revolutionary narrative.
I don't support "gay marriage," but I do think that one of the benefits of a lesser stigma attached to homosexuality (i.e. its decriminalization) is that it creates fewer sham marriages where the homosexual partner endangers the health of his spouse and children and, health issues apart, inevitably engages in secretive behaviors that will eventually lead to a broken family. A good friend of mine is the son of such a sham marriage, and I never envied him or his mother their circumstances. I guess his only consolation was that without his father's need to be a closet case 40+ years ago, he would never have been born.