This all looks very clear to me...
You almost definitely have an oral HSV1 infection. With no known outbreaks you were probably infected before 3 years of age and have not had outbreaks since. This is very common.
Once you are positive for on form of HSV, IgM testing is then useless. What is being detected could readily relate to your HSV1 infection or simply be a false positive.
With no sexual contact for 18 months, the negative IgG for HSV2 is all the proof you need!
Silly doctor... but all is OK rgarding HSV2, you do not have it!
Note: I have not had any outbreaks on or near my genital area. However, I have looked at it more in the past two weeks than I have in my entire life combined :)