?Doctors responsibility of informing on an STD?

If a patients spouse has an extra-marital affair and contracts and STD (Herpes 2) does the treating physician have a responsibility to inform the other spouse of risks, if they are the primary Physician to the couple?
Update: To Curious....

I wondered the same thing, especially after being together for 7 years and suddenly hearing, "we can't tonight, I have an outbreak... remember, I told you I had Herpes on our first date..... " Yeah RIGHT!
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