I think you've already made up your mind, and are hoping to see her bashed in this forum to make you feel better about your decision. After all, nobody here is unbiased - we wouldn't be here if we didn't have some axe to grind.
If you can't let this stuff go, definitely don't marry her. If you love her, you'll do her and yourself that favor. Don't marry someone you are constantly going to badger about a past they can't change. Don't make yourself crazy over that past. Particularly if a kid is involved!
Constantly bringing up her past and questioning her about it IS punishing her. It lets her know every time you do it that you don't approve, that you think less of her, and don't trust her.
What could she possibly do, ever, to put you at ease? Nothing. She can't fix your insecurities - only you can do that, and only with a lot of work.
Sounds like you are much more upset by things having to do with the other guys than with the herpes itself, which makes me think that your concern is more that she will cheat on or abandon you than anything else. Do you have a major abandonment issue that you could address with counseling? Sometimes when there is something concrete and obvious, it is easier to "fix."
If you think this is a relationship you want to save, ask her to go to couples counseling, too. But work on yourself, or you'll dismiss what the therapist says just as you dismiss what i said about most women not being size queens. (Google that issue, since you don't believe me. Ask Dan Savage or something. I'm not making it up.) When your insecurities are deep rooted, you twist what people say to prove what you want, no matter how correct the other person is.