vaginapagina | Herpes disclosure

The recent post about herpes brought up some questions for me.

My question is: Is it always necessary for an infected person to tell a potential partner?

From a theoretical standpoint, YES! Yes, yes, yes! But consider a few scenarios:

You haven't had an outbreak since your first one--15 years ago. As most of us know, herpes is transmittable even when the infected person doesn't have a sore. However, plenty of us infected people just avoid sex/kissing when we have a sore, and the other partner is fine. Do you still let your partner know about an outbreak you had at 20, when you are now 35? Do you risk ruining the whole relationship (because people generally freak out when the word "herpes" in involved) over a nearly negligible risk?

You have oral herpes. Studies show that 80% of us have herpes antibodies, and might be carriers of the disease without even knowing it. Yet I've never, ever heard of someone fessing up before a liplock. Do you let everyone you are about to kiss know that you have oral herpes? I personally feel like everyone is aware of--or should be aware of--a certain risk that's involved with intimate behavior like kissing or sex. You could catch mono, a cold, the flu, herpes, et cetera. You do what you can to prevent it, but it's still there.

For that matter, is there a difference between disclosing about oral herpes (which you can write off under the more innocuous name of cold sores) and genital herpes? Do you have more of a responsibility to tell a partner about genital herpes? And why?