I have explained to him that one of my former metamours contracted HSV genitally, from oral sex, and that this is part of the reason that I take this extremely seriously. From what I understand, it can be painful and debilitating and I do not want to risk that happening to me.
Fair enough. You do not want this so you choose your behavior to protect YOU from this.
I am still afraid FOR him, too...the last time we talked, he seems to be justifying his possible involvement with this person, for instance: "Well, people who have had it longer don't shed virally as much, and X percentage of the population has it/has been exposed to it, and she had a partner for X amount of years and he never got it..." (oh? How do you know? How does SHE know? Sigh.)
It is frustrating to care for someone who does not seem to value themselves and their well being as much as you do. But his behavior is on him. He chooses his behavior. He lives with the consequences.
You could step out of the line of fire to protect you so you don't have to bear those consequences directly.
would be zero people going down with the ship.
If he's hell bent to go down with the ship, that is ONE person going down with the ship then.
You making it TWO people going down with the ship is not an improvement upon just one person going down. You can swim for the shore instead.
Because if you are going to be worrying about him either way? Could at least get YOU to safety and worry from the shore then.
Take care of you.