I understand that our reactions to these types of things aren't always rational, but stand back and take a look at what you're saying. You told your BF beforehand, he said he knew he might get it and was okay with it, and even encouraged risky sex. Now it looks like he might have it and he's still okay with it. And if he does end up having it... he's not going to want to be with you anymore? That makes zero sense. None. It sounds like the issue is not your BF, at all, but your difficulty dealing with the insecurities herpes can make us feel about our bodies and relationships. Don't let that muck up your relationship, because this guy seems pretty chill. Instead, try to follow his lead and if you can't, try talking to a counselor.
Do you like this guy? Then trust what he says and don't project your anxieties onto his motivations. That's a disservice to you both. Also,, not for nothing, a lot of people here would kill for a partner like that!