Consider giving them reading material or referring them to a sexual health centre or the Herpes Helpline or this website, to verify the information you've given them. Some people might overreact, and some people won't bat an eye. Given the number of people with genital herpes, many people have heard this story before. Whatever the reaction, try to be flexible. Remember that it took you time to adjust as well.
Negative reactions are often no more than the result of misinformation.
In some cases they are brought on when persons fear that you're asking them to commit to a relationship, instead of just informing them of the situation. If your partner does decide not to pursue a relationship with you simply because you have herpes, it's in your best interest to find out now. It takes a lot more than the occasional aggravation of herpes to destroy a sound relationship. Some people react negatively no matter what you say or how you say it. Others might focus more energy on herpes than on the relationship.