A couple in which only one partner is positive is called a single-positive family. If the HIV(+) partner is not on antiviral treatment, both partners will recognize that they must have protection when having sex. However, when the HIV(+) positive partner is successfully treated with antiretroviral therapy and the amount of virus in the blood is no longer detectable, this awareness of protection fades.
But recent studies have shown that in some HIV-positive people, even if the virus in the blood is no longer detectable after antiviral treatment, the virus may still be present in the semen, so even if the antiviral is successful, protective measures should be insisted on to ensure that the HIV(-) partner is not infected.