Hi cytra,   Thanks for posting your question.  Although I'm not a doctor, and so cannot give any medical advice or statements, I do have herpes and am fairly knowledgeable about the disease.  The answer to your question is that yes, there is a chance that he could get infected from just one time, and yes there is also a chance he didn't get it.  It depends on how contagious you were at the time you were with him, and how careful you were while having sex.  The only way to know for sure would be for him to have a blood test.  If you are worried about this then you should always practice safe sex, refrain from having sex during an outbreak, and check out some of the posts on HealthCentral.com like Preventing Herpes, Dating and Relationships, and Causes and Risk Factors.   Good luck!    PJ