90% of infected people have no recognizable symptoms of herpes at all.
which is one reason why it's very difficult to figure out where a case of herpes came from. Another possibility is that you have HSV1 genitally. About 1/3 of genital herpes cases are type 1 almost always acquired from someone with oral HSV1, AKA cold sores, performing oral sex on you.
Since your diagnosis was 18 years ago, I'm guessing that your genital case was not typed. Back then, the assumption was made that if the herpes was "down South" it was type 2. Better testing available now has proven that to be a bad assumption.
If you are still having recurrences, I'd suggest that the next time you have one, you get a type-specific culture or PCR swab done on it while it's active.
As far as being a "carrier" that's not the way it works. You either are infected with the virus or you're not, but, as I pointed out in the subject line, there are a lot of people who are infected and don't have a clue about it.
Let me know if I can help further.