Hetero HIV seroconversion rates
The ultimate study on HIV serodiscordant hetero couples was done by Nancy Padian, et al, chief epidemiologist of UCSFC.
The Padian study which was conducted for over a decade showed that it took an average of 1000 acts of intercourse between a seropositive male and a seronegative female for her to statistically seroconvert. The seroconversion rates from a seropositive female to seronegative male where he seroconverts from sex with his seropositive female partner were even lower.
Your chances of HIV seroconverting from sex is almost non-existent, and there was lots of discussion on Magic Johnson frequenting homosexual bars which the news reporters were starting to snoop around till he retired the 2nd time.
If you are worried, I suggest you wear a full face helmet when you drive as you're far likelier to be killed in an auto accident that HIV seroconverting from having sex with bargirls, and a full face helmet is far likelier to protect your health than a condom is.