Is there an antiviral medicine that I can take that would hinder the spread of herpes?

Yes. There are several antiviral medications that help prevent the spread of HSV. None is 100% effective. Taking one of these medications daily can reduce recurrent outbreaks. It is possible however for a women to have asymptomatic shedding of the virus even while taking one of these medicines. She may unknowingly spread the virus during this time. Condoms help prevent transmission.
ANTIVIRAL MEDICATIONS. YOUR PCP OR A DERMATOLOGIST CAN GIVE PRESCRIPTIONS FOR ACYCLOVIR, VALACYCLOVIR, or OTHERS IF HE OR SHE THINGS IT WOULD BE NECESSARY. CHECK IN WITH THEM. BEST LUCK.
What kind of Herpes? Yes there are antiviral medications available for different herpes infections, see your doctor to decide on indication and dosage.