She is a liar and is really engaging in bad behavior. I agree, herpes isn't that big of a deal. But to some people it is. She knows that it is a problem (that is why she is lying) and yet she goes ahead anyway just so that she can get what she wants. That is selfish and immature. The fact that people should go ahead and accept the risk does not remove their right to informed consent in the first place.

Compare it to being a vegetarian - if somebody accidentally serves a vegetarian something with animal in it (its in a lot of places you wouldn't imagine!), well no real harm done but they should be educated to make sure it doesn't happen again. But if somebody deliberately sneaks in a little animal then that is asshole behavior. In the same way, somebody accidentally spreading herpes should be educated but somebody deliberately sneaking around to do it is just an asshole.