Unfortunately, we don’t have statistics on the transmission of HSV 1 because it is so uncommon. The correct statistic is that 56% of the adult population between the ages of 14-49 have HSV 1 infection – we don’t know where those infections are, only that they have antibody. The younger the person, the more likely it is that they have it genitally vs. orally. Has she been tested to know if she has HSV 1, do you know? Has she ever in her life had a cold sore on her lip? If the answer is yes to either, then she is not vulnerable to your genital HSV 1 infection because she already has it somewhere. I do think you are on the right track to tell her, I would if I were in your situation.
Terri