It is more imporant to make allowances for social custom to slow this pandemic then it is to worry it will lead to marriage between gay and lesbians.
Every additional infected person endangers - and costs - this nation. I would rather see gays and lesbians stick to one partner then to sleep around.
And the only way I see that happening is if there is the social incentive of some form of sanctioned social bond between these people.
Less of a culture of "sleeping around" in this sub-culture makes it less likely bi-sexual men will bring something home to their wives.
I am not saying my suggestion is perfect, but anything done to cut the rate of spread of HIV that works seems to me to be worth doing.