My friend was recently dating a guy who repeatedly told her how much he liked her, called her his 'girlfriend' and said that he was after a serious reationship. The dated for about 6 weeks, him continuing to be attentive and interested. When she finally had sex with him, (being the kind of girl who wanted to get to know a guy first) he dumped her by text. He pretended he was really interested in her as a person, waited until he got laid, then dumped her. And she is an extremely beautiful girl.
Honestly, I don't think it had ANYTHING to do with your genital herpes and how you told him. I think he just, to use your words, 'blew you off like some stranger' once he got his wicked way with you. Honestly, don't take it as a comment on your herpes. I really think he was just a jerk.