Specifically receiving oral, no vaginal sex. Using condoms is very important. Further, whatever transmission chance exists is further reduced by your partner's antiviral therapy. 4% chance transmission from female to male; No risk if her hsv 2 infection is genital.
Cold sores contain high concentrations of the virus and hence increase the chances of transmission significantly. If partners also use condoms and antiviral medications: Using condoms is very important. Specifically receiving oral, no vaginal sex. Further, whatever transmission chance exists is further reduced by your partner's antiviral therapy. I've only had one outbreak, as far as i know, and the only symptom that i can recall was an incredibly bad pain in my lower back, which my doctor seemed to think did not suggest herpes. Transmission is easier from a man to a woman. The reason is just the natural way female and male bodies function and interact.