You might have it. Your hsv1 blood test could have missed it - the IgG herpes blood test misses 30% of infections.
Were you diagnosed with a culture 20 years ago? If you were, you can count on that being reliable. A culture is far more reliable than a blood test. Ghsv1 rarely sheds - by now, you are probably shedding about 4 days a year - and many people only get 1 initial outbreak of it.
If you don't have an outbreak, it's virtually non-transmittable.