Hello and welcome to HCM.
Thank you for your query.
A weakly positive IgM, indicates recent infection, which is apparent with your recent sexual contact. But, it could also be a false positive, as we get a positive IgM during the presence of other infections as well (although rare).
Your partner can test negative for it as she can just be a carrier, so there could be no point in asking her to get herself tested.
My advise would be to wait 3-5 days, and get yourself tested again. Consult your doctor for antiviral
therapy at the same time.
I hope I have succeeded in answering your questions, you could write back to me anytime for further clarifications.