It is possible that HSV 1 genitally may offer some protection against HSV 2 genitally, that is correct, but that is not definite. Also, we don’t have a realistic estimate of the risk of contracting HSV 2 at a single encounter. We just don’t. We do know that for people who contract HSV 2, they often have few encounters before contracting it. But then a whole lot of people don’t contract HSV 2, even after multiple exposures to the virus so we just don’t have the information that you seek. Condoms reduce transmission from men to women by 95% so they are a good tool to have around.
Terri