I have been in a similar situation. I found out I had gHSV about a year ago, when I accidentally infected by girlfriend (now ex). Its a terrible feeling, especially because of what she was going through with her first outbreak, so I kind of know what you're going through there, and I'm sorry for you.
As far as fearing you'll be a constant reminder, I definitely felt a similar way when she first brought up her outbreak to me. I asked her if she wanted me to go to the clinic with her, because I really wasn't sure if she'd want me around at all. Thankfully she was extremely gracious through the whole process. I think the best thing you can do, is to offer your support, and be there when she wants it. I would stay over at my girlfriends house, and hold her when she was shaking after having to endure using the restroom, and of course I apologized a million times or so. She and I ended up breaking up for different reasons, but I would definitely say that the experience actually brought us a lot closer together than we would have been if we hadn't gone through it.
I always wished that she would have ended up with someone else, and that I would have never given it to her, but I also can't imagine what it would be like going through something like that alone. Its a double edged sword, the guilt of unknowingly passing HSV on to someone is terrible, but at the same time, it can be so helpful to have someone else to go through this with. Hopefully she can forgive you, and you both can appreciate the blessing of having someone else to go through this with.
Your situation sounds really similar to mine, so message me if you ever wanna talk.