I have recently been diagnosed with herpes. I have read that you can pass it to someone who performs oral sex on you even if there are no symptoms or outbreak present. You can pass it to him through viral shedding. So, the answer to your question: there is NO guarantee to not spread it unless abstinence or no oral sex. There are better times to do it than others, but usually a person does not know when they have viral shedding--which can allow the virus to be transmitted. He can use oral dams, condoms--BUT again, this is not 100% guarantee.
Valtrex is supposed to help with outbreaks and reoccurances.
If you have oral sex, just don't do it while you have symptoms (tingling sensation, burning sensation, leg pain, lower back pain, itching, or the obvious-an outbreak). Again, you can use oral dams or condoms, but it's not 100%.
Hope that helps.
Please repost your questions in the correct forum. STDs Forum