Welcome to the forum.
First, your assumption is wrong; it is statistically unlikely your commercial partner had an active, transmissible HBV infection. And if she did, the chance you would be infected after a single unprotected sexual exposure is probably under one in 1,000 or something in that range. And your risk might be even lower, given your past immunization; even though you only received one dose, you probably were at least somewhat protected. If you had come to my clinic, we also would not have recommended you receive HBIG; the risk is too low.
In other words, I agree with the hepatologist that you should not receive HBIG. The most common use probably is in babies born to infected mothers, but there certainly are situations in which it would be given to adults. But not when the risk is as low as yours.
Best regards -- HHH, MD
Wow, thank you very much. My anxiety and ocd was messing up how I saw this. Thank you. They are testing me for everything so between that and your input , it is a bit more in perspective now.