It does sound like this was a recurrence, not a new infection, by the physical presentation.
The index value is almost never zero – it has a value almost always and the 0.8 is negative. How long before you had the positive swab test did you have sex with this person who tested negative at 0.8. This is a higher negative and it could be that he is in the process of going from negative to positive, which is a concern.
The anal itching that you had could have been a new infection with HSV – not possible to know at this time.
The sexual contacts that you had – were the protected or unprotected?