The risk in respect of Hep C is minimal, virtually none at all, unless for some reason blood was combined. There are many cases of people who have been married for 20 years plus, having unprotected sex, and no Hep C passing. I don't know anything about Hep B though - you might want to try that board.
There has been a lot of discussion on this topic and different organization may or may not classify HCV as an STD (the U.S. Military does). I think the consensus is as Moahunter describes. Hep C is very unlikely to be transmitted during sex, although it is always possible to construct a hypothetical situation where it might be. I have had it for about 40 years and my wife is not infected.
CDC says condoms are not necessary (regarding Hep C) for monogamous partners, but recommended for protection in "risky" sex (not sure what that means). This is because Hep C is transmitted ONLY from blood to blood and not with other bodily fluids. This means shared needles, etc.
Hep B, on the other hand, is very likely to be transmitted through sex. That is the primary vector for Hep B. I suppose a condom would help but they don't eliminate the risk of contracting HBV entirely.
If you think you are at any risk of contracting Hep B, get the vaccine! Get the vacine, anyway. I think it is standard now to vaccinate children.
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