My questions are:
1. If I’ve contracted OHSV1 from him, despite already having antibodies from my previous GHSV1 infection, do you think the antibodies I already have will help regarding recurrences/shedding of OHSV1?
Yes, definitely, and it is also unlikely that you would acquire HSV 1 in a new location after having it genitally.
2. He gave me oral sex, how likely is it that this “reactivates” my GHSV1 that I’ve had for 10 years, regarding frequency of shedding and outbreaks?
Very unlikely. From a science perspective, there is nothing that would trigger a recurrence in this situation.
3. I gave him oral sex, how likely is it that I’ve spread it to his genitals since he’s already had OHSV1 for a few years apparently?
Very unlikely indeed.