No, Aids infection rates in homosexual men have declined over the last decade as many jurisdictions legalize gay marriage. When Partners engage in a monogamous relationship the risk of catching the HIV virus drop to near nothing, but since HIV is a blood disease the risk of infection is never going to go away. Promiscuity is the real issue here, and many people with HIV/AIDS are on antiretroviral drugs and will make their status known to their partner. When an HIV positive person receives treatment risk of transmission drops by over 90%.
your Question also shows a level of ignorance about how HIV/AIDS works. HIV cannot be conjured out of thin air, and Having anal sex with a partner will not spontaneously cause the disease to manifest in either person. You have to have intercourse with someone who is HIV Positive, But the risks of that drop when people are in a committed relationship, Legalizing Gay Marriage will actually cause infection rates to drop as more men enter into committed partnerships or become more open about their sexuality.
The AIDS epidemic first ravaged the Gay community in the 80's because in those days we kept quiet about our sexuality, there were fewer men in long term relationships and even the ones that were wouldn't be open about it. People would engage in one night stands more often and they were less open about their sexual history.
Infection rates among Gay men have dropped in the last decade so substantially that we are now no longer the group with the highest susceptibility, the people most at risk of new infections are Actually middle aged heterosexual women, and senior citizens. Gay marriage will not cause a spike in HIV/AIDS infections, at least not in the Gay Community, we cannot guarantee a spike in infections in other demographics will not happen.
HIV/AIDS is an insidious disease and the fact that it's origins on this continent were in a stigmatized group make spreading AIDS awareness in america difficult, and i can guarantee if patient zero had contracted HIV through blood transfusion and had not been a Homosexual man we would be further along in AIDS research today than we are, we would possibly even have a cure by now. Social Stigma is the worst thing you can have while fighting a Pandemic.
Educate, Fight, Start a Conversation about HIV/AIDS, practice safe sex and encourage honesty with your partners, male or female. AIDS does not discriminate and we are all at risk.