While HIV/AIDS was initially basically a disease of gay/bisexual men, it crossed over to the heterosexual community pretty quickly. Recognition was delayed due to not looking for it and also the latency between infection and obvious symptoms. While initially there be more of a anti-gay backlash, once HIV is seen in the heterosexual community the backlash against prostitution for example will be equally harsh. It is still not clear the POD date for this, but lets assume its the late 1940's brought back to the USA and Europe by servicemen who served in the Allied bases in tropical Africa.
Sexual revolution, forget about it. You'll see a return to strict morality that is now backed not just by religious rules, but the reality that one encounter can give you a fatal incurable disease - unlike syphilis and gonorrhea which by the late 1940's are curable with antibiotics. Dating, in the sense of young men and women going anywhere without strict chaperonage will cease. Female virginity, possibly confirmed by premarital examination (which occurs in some places now) will rapidly become the norm. Extramarital affairs, when exposed, will result in the scarlet "A" for the offender male or female, and I expect automatic divorce with the guilty party losing all parental rights, and taking a huge financial hit - the breadwinner hit with huge payments to the other spouse, or the non-breadwinner denied payments. Homosexuals and bisexuals (male) will face huge issues, and of course any person with HIV may be quarantined - although this won't be until they have symptoms, and folks with the disease may be denied medical treatment (waste of resources etc.). It is not unrealistic that lesbianism, especially among teenage girls and young women before marriage, may be winked at since this is the one form of sexuality that is safe.
Of course, the reaction to HIV/AIDS will be a huge increase in effort and funding for medical research that will make the search for new antibiotics and the polio vaccine look like nothing. Understanding of viral diseases, treatment for viral disease (as opposed to bacterial disease). The changes in society such as I outlined will last quite some time, although eventually the pendulum will swing.