Well, I don't think that ther's even such a thing as "harmless carier"!!! Back then from what I've read and heard...doctors thought that as long as you don't have symptoms you're not contageous which is proved to be absolutely wrong and that's why the doctor told you not to worry back then.
From the negative and then positive HSV2 for your wife, you're right it's a recent infection from some one else but that doesn't guarantee you're a harmless carier it just means that she didn't get it from you! And usually people shedding rates becomes much much lower with time and if I understand you correctly, you've been infected for atleast 12 years (who knows if it hasn't happened way before that, right?)
But you can still shed and infect for both types and my guess is that you have type1 orally and type 2 genitally but show no symptoms and that's it. Any way, you have nothing to worru about as you have both types and your wife won't re-infect you.