consistent condom use; and taking anti-herpes suppressive therapy like
valacyclovir. Genital to oral transmission is uncommon, but could occur. However, if it's HSV-1, the risk of transmission (for either genital or oral sex) probably is quite low.
Also, has your partner been tested to determine for sure whether she has genital herpes? She could be tested to learn whether she is susceptible to HSV-1 or HSV-2, or perhaps previously infected and therefore immune to a new infection.