not understanding...

i've read the recent article about genital herpes and it pushed me into writing this. i'm 19 and was introduced to a guy from a very close friend. we were getting on really well until i slept with him and caught genital herpes. i kept it to myself for a few days and went to the doctors for it to be confirmed. i confided in my friend who had told me she knew he had it from his ex-girlfriend, i then told the guy he had passed on the virus to me. i'm struggling to understand it all as the guy is adoment he didn't give it to me as his doctor said he can't pass it on without a sign of a sore, 'which he didn't have', i have been forced inside to think that maybe it was something i done? how else can i catch it?. i was in a relationship for a year before this guy and would of thought that i would of had signs before if it was him so theres no other way i could catch it, but don't want to take the blame for it as it's hurting me more.