MedlinePlus is an authoritative source of consumer health information from the the U. S. Library of Medicine. The guidelines below are from their Medical Encyclopedia.
Preventing the Spread of Herpes Even when you do not have sores, you can pass (shed) the virus to someone during sexual or other close contact. To protect others:
Let any sexual partner know that you have herpes before having sex. Allow them to decide what to do.
Use latex or polyurethane condoms, and avoid sex during symptomatic outbreaks.
DO NOT have vaginal, anal, or oral sex when you have sores on or near the genitals, anus, or mouth.
DO NOT kiss or have oral sex when you have a sore on the lips or inside the mouth.
DO NOT share your towels, toothbrush, or lipstick. Make sure dishes and utensils you use are washed well with detergent before others use them.
Wash your hands well with soap and water after touching a sore.
Consider using daily antiviral medicine to limit viral shedding and reduce the risk of passing the virus to your partner.
You may also want to consider getting your partner tested even if they have never had an outbreak. If you both have the herpes virus, there is no risk for transmission.
Another authoritative source of information on this topic is the Genital Herpes Fact Sheet from the Centers for Disease Control and Prevention.