How where you diagnosed? With a swab of the sore? Is it HSV1 or HSV2? Since you were diagnosed in August, I assume you have been sexually active before that with your current boyfriend?
OK… Hold up. You were diagnosed, I assume via a swab, with HSV one. I believe, if your boyfriend was the one who performed oral sex on you before you had your sore, he is the source of your infection. That means, he has HSV one orally. If he already has HSV one orally, it is highly highly unlikely for him to get it in a new location. He already has the antibodies. HSV one genitally sheds infrequently and usually causes infrequent outbreaks. I think you’re worrying about nothing. I know the diagnosis is a shock but since this is something that you more than likely got from him, don’t worry about passing it on to him.
When this blister showed up, did your boyfriend perform oral sex on you a few days before hand? Did the previous partner you had perform oral sex on you? I understand feeling guilty and it sounds like you’re beating yourself up for this. But stop. I know it’s easier said than done but try. HSV one is incredibly common. Doesn’t matter if you have it orally or down below. I think that your current beau is the source of this. Most people who have HSV, whether one or two, have no symptoms. Even without the symptoms, they can pass the virus. HSV one in the genital region is 99.9% of the time passed via oral sex. Genital to genital transmission of HSV one, is superlow. Actually, if you ask Terry Warren who is a leading expert on HSV, I don’t think she’s ever seen a case of it. You made a mistake. So many people make the same mistake. It sounds like you two have worked through it. Now you have to work through this and realize that your risk to him is so very low, but he could have this already.