Sorry to hear about your diagnosis, but you should be aware that herpes is a manageable condition, and will tend to occur with diminishing frequency and severity as time goes on. Many people even stop noticing symptoms after just a couple of years. The first one or two outbreaks are often the worst. After these, symptoms will generally not be as severe.
To answer your question, outbreaks tend to occur in response to certain triggers. These include a weakened immune system, drinking too much alcohol, or wearing tight underwear or exercise clothing.
So perhaps one of the best ways to limit the risk of an outbreak is to make sure you look after your immune system and make sure you're getting enough sleep at night.
It's a good idea to have a healthy balanced diet anyway, and not drink too much alcohol; not only to reduce your chances of an outbreak but to ensure your overall health too.
Herpes is much more likely to be transmitted to someone else during a flare-up, so sex while you're experiencing symptoms is a definite no-no. This could also make your own symptoms even worse.
Although not as likely, however, it is possible to transmit the condition when symptoms are not present. This is called asymptomatic shedding.
Generally, it is better to wait for at least a week after symptoms have completely cleared before engaging in sexual intercourse; and using adequate protection (such as a condom) when doing so. It's always a good idea to talk about your sexual history with your partner before having sex, and taking adequate precautions.
There is plenty more information and advice on herpes to be found on sexual health charity websites such as Brook and FPA (Family Planning Association).
Things that adversely affect your immune system and run your body down are said to trigger outbreaks in susceptible individuals, so insufficient sleep, a messed up body clock due to jetlag, steroids, excessive alcohol and a very poor diet, etc.
However, despite what many websites and people claim, there is no scientific proof that certain foods are good/bad for herpes, not even lysine. My doctor at the STD clinic did not recommend I change my diet, and I have no intention of doing so, although I have since switched my herbal teas to echinacea, lemon balm, liquorice root and St. John's wort.
Of course, if you strongly feel that a certain food is somehow triggering outbreaks, then you should probably eliminate it from your diet.
Hannah If you go to holland and barrett get some l-lysine tablets, I have taken it for about two yrs and its really lessened the outbreaks but for some reason lately i havent taken it and ive had two outbreaks in a very short space of time so im back on it pretty quick. 1000mg is what you need x