That does seem to be the case. There is also a theory that maybe as people are exposed to bacteria and viruses on their lips, including HSV1, that defenses are developed more strongly in that area.
I looked around on the Expert forums, and apparently it's pretty much impossible to catch HSV1 on the genital area if you've had it on your mouth already...and the longterm partners who eventually caught it, were never infected with HSV1 in the mouth their entire relationship so they were susceptible to catching it on the genitals.
Thank you for explaining it so well. Do you think it would still be possible to catch genital HSV1, if the partner was already infected orally with HSV1 from a different partner beforehand?
This is hard to comprehend sometimes, but does illustrate that the virus has to be present, which it is only at certain times, and must be rubbed in and reach a nerve. Hence although the same episode resulting in a genital infection may also involve kissing, each site was exposed to a chance of infection only.