Hello and thank you for using HCM for your questions! The situation you are experiencing is fairly common among persons engaging in oral sex. The answer to your question is: both or all scenarios might be possible. It is possible that you have it, the first girl could have it or the second girl could have it. HSV is very prevalent, meaning that many people are infected but luckily in the overwhelming majority of cases there are no permanent consequences on health, as people can have HSV infection and live a happy and healthy sex life. Also, infected people might have no signs or symptoms at all and they can spread the infection to other sexual partners (HSV2 virus) or other people (HSV1, through kisses for example). HSV2 is mainly transmitted through sexual intercourse but oral sex can spread it as well and the virus can cause mouth and lip sores, etc. There is no cure and little can be done to prevent the infection, but the symptoms usually resolve within days. Antivirals could be used to alleviate symptoms but only when they are really disturbing. To close this answer, I think that in this case no one has to be blamed about having the HSV as it is very common and it is very difficult to be protected from it! I hope my answer was helpful and I wish you all the best!