To begin with, it is important to know that you are having unprotected sex with your partner who is on treatment or not on treatment. A person who is HIV positive, who is on an effective treatment with his sustained viral suppression, which means his virus is totally under control because of the mediation and if not the partner are having this sustained viral suppression, it is safe to have a unprotected sex because there is no transmission or transfer of transmission of the virus or a resistant virus which is more common nowadays. It is okay, but both the partners have to have a suppressed viral suppression. Also it is important to know that the unprotected sex between two partners does not mean that there cannot be a transfer of sexually transmitted infections, that means not just HIV. But their infections like gonorrhoea, chlamydia, fungal infections, these infections can sill be transmitted with unprotected sex. So get yourself checked for viral suppression and for other STI’s as well.
source