Well, yes, I would agree that a doctor who can correctly interpret lab tests would be useful. If you have no concerns about your husband having other partners and you know that you have not had other partners, then retesting is not going to be helpful at all because nothing has changed. Now the exception would be if your husband has had herpes for a long time and didn’t know it and just infected you. Has he been tested? If not, that might be a good idea. If he is HSV 2 positive, then retesting would be in order for you.
One possibility is that you have HSV 1 genitally. Have you ever in your life had a cold sore on your lip? If yes, then it is very unlikely that this would be new HSV 1 genitally.
Another possibility of course is that the blisters are not herpes. It was good that he did a PCR rather than a culture. Frankly, I’m surprised!
You are correct that IgM tests are useless.
So my recommendation is 1) get your husband tested for HSV 2. If he is negative, you can take this off your list
2) If you get this again, have another PCR done to see if you might have HSV 1 genitally.
3) don’t change anything about your sexual relationship at this point – no need.
You have two more posts for me if you have more questions.