People may mistake symptoms for other ailments, such as jock itch, bug bites,
heat rash, etc... Have you spoken to the unprotected partner and asked if they have experienced symptoms of GH, or have been tested since your encounter? If not, you should try.
Generally, before a GHs outbreak, you experience what is termed "prodome". This generally presents with tingling and reddening in the area where the outbreak will occur.