"Inoculate" yourself? What does this even mean? You mean infect yourself somehow other than through sex? Why would you want to do that?
It sounds like you just need some education about transmission stats. It's not that easy to get genital herpes, and that is especially true in your case - a monogamous relationship with a person who knows he is infected and is on medication.
The risk to you with him taking drugs is probably not worth worrying about. You've probably got a higher risk of dying in a car accident.
Give the guy a break and bail on him if you can't handle the risk - and let him find someone who can. You are very fortunate that he was honest with you - many people wouldn't be. Seriously - if you can't wrap your mind around this, why are you even with him?
It seems like she can wrap her mind around it and has already worked it all out. I think she just wants to know how best to go about protecting a potential child. From what I understand, neonadal herpes is pretty deadly to the infant.
If he's on suppressive therapy, you avoid sex whenever he has any genital symptoms and you use condoms - it's a 2-3% risk each year of you contracting hsv2. Even when you stop using condoms to conceive, it's only a 4-5% risk each year of you contracting hsv2 from him. Once you are pregnant - you can go back to using condoms again if you wish to keep your risk low while you are pregnant. You really should be more surprised if you do contract his hsv2 than if you do. No reason to try to get it when you can keep your risk of contracting it from him so low in the first place don't you think?
If and when you are ready to start a family with this fellow, get a type specific herpes igg blood test at the beginging of your pregnancy and then repeat it at the start of the 3rd trimester. If you are still negative for hsv2 at the start of the 3rd trimester it's recommended that you avoid sex until after you've delivered but that's totally up to the 2 of you at that time. Cross that bridge when you come to it.