All I can tell you is that my uncle was positive all the time he was married to his second wife-they were married for about thirty years and had two kids together-and she's negative. My two cousins, my little brother, and I all grew up with positive parents (their dad, both of my parents) who didn't know they had it and we're all negative.
Hep C. isn't very easily transmitted. The government's own health website lists sexual partners of Hep C. positive people at low risk for contracting the disease. If all you had was "oral contact" with no open wounds involved, you're at extremely low risk. Wouldn't hurt to be tested any way, but I think you probably have reason to be optimistic.