Most folks who have hsv have no idea they have it until they get tested. No way to know when you contracted it and from whom by the blood test results. Yes indeed it's not only possible but probable that if you had hsv2 prior to meeting your partner that you didn't transmit it to her.
Your partner probably wasn't tested for herpes during pregnancy. She'll need to call monday and find out if she was or not. Is she still pregnant or did she have the baby?
Once your partner confirms her status, discuss together what precautions you want to take together. The herpes handbook at www.westoverheights.com
is a good resource if you need more than just the herpes info on the main asha site.
keep asking questions!