It is true that people who don’t have recognized outbreaks do shed less, correct. And you will shed periodically from the mouth as well. And it is common to shed from both sites at the same times, I suppose because something causes the immune system to dip a little and the virus to emerge. You only shed HSV 2 from the genitals and HSV 1 from the mouth.
If you take daily medicine, you can reduce the risk of infecting someone else by almost 50%. That’s huge, in my mind. And some medicines need only be taken once per day (though the cheaper and just as effective medicine is twice a day). If you take medicine daily, the risk of infecting him is about 2% per year – which means if there were 100 uninfected men having sex one on one with 100 infected women, having sex about twice per week while taking medicine, no outbreaks and he knows, 2 men would get infected, on average.
We don’t have statistics on HSV 1 transmission via oral sex but we do know that the medicine works on HSV 1 as well. At age 48, a large percentage of people already have HSV 1 and I’m guessing he might as well. When you tell him, I would suggest that he get tested – 80% of people with HSV 2 don’t know they have it. The proper test is the HSV 1 and 2 IgG and this can be done on the internet without a clinician order.
By the way sun is a trigger for HSV 1 so be careful to use abundant sunscreen when you are outside.