Trying to live and deal with herpes?

Hi guys, so the other day my boyfriend went to the hospital with me to check out blisters on his shaft. Turns out the results came back as Genital herpes. Me and my partner have been together for over a year and neither one of us has cheated. So we don't want to play the blame game but I have never had any symptoms or any signs to which this would have came from me. I still don't whilst he does. So would anyone have any info on how it spreads or if it did come from me why it wouldn't have shown any signs? Thanks!