First off - have you been tested yourself to know your own herpes status? if not you should get one done. Assume nothing.
I encourage you and your gf both to read the herpes handbook at www.westoverheights.com. It's a terrific resource an dit's free!
If you are hsv2 - and your gf is hsv2+, if you two did absolutely nothing but avoid sex during obvious genital symptoms on her, you'd have on average a 4% risk per year of contracting hsv2 from her. If she takes daily suppressive therapy with valtrex, your risk is cut in half. Throw in condoms along with that and you are looking at a 1% risk/year on average of contracting hsv2 from your parter. Pretty reasonable odds for the most part, in fact if the only birth control she used was the pill, that's a 1% risk/year of getting pregnant ( gives you something to compare it to ). Talk to her about this and ask her what precautions she is willing to take.
Kudos to you for coming here to get accurate info instead of just hearing herpes and running away!!
grace
the only protection you really got is latex condoms and if you want to have sex try it when shes not having an ob but the only medicine they got is to control or shorten your outbreaks but auntijessie knows way more about this im sure she'll talk to you about it.