I (27M) messed up with my fiancée (24F) and I don't know how to fix it.

To preface, I would like to say this is my first real relationship, and the first time I've ever gotten close in any way to another person. We haven't kissed yet, and I have never kissed anybody before.

So, a few days ago, I was spending time with my fiancée. I was comforting over something she was worried about, and we started hugging. One thing led to another, and we got very comfortable, eventually to the point where we were almost kissing. This would have been the first time for us and me, but not for her. The thing is, she wasnt completely comfortable with this, and I just couldn't tell at the time, so I didn't pull back immediately, and she had to. The only explanation I have for what I did is a lack of experience and dreadfully poor judgement and self-control in this situation, but excuses won't help, the effect is she was very hurt. She explained that she had bad experiences in this way before, feeling used, and that she was so disappointed in me, because she thought I was different. She said she'd forgive me, but I don't know how that's possible, and I don't know how she'll ever look at me the same way again. It's also very obvious since then that something has been broken.

This whole thing has been eating me up inside, and it's shattered every notion I had of myself, as being respectful, thoughtful, caring, whatever. I just don't believe in myself anymore. I know I was very wrong, I know I hurt her badly, I knew it almost immediately just after the moment, when I regained my senses, and I've apologized to her over and over again, but I just can't forgive myself. I don't know how to make this right. I don't know how to get back to the way we were or to move forward. I want nothing more than to be with her, and I know for a fact I'll recognize her boundaries completely from this point on, but I'm breaking apart over what's been done, and I can't undo that.

I'm asking for advice on what I can do to make this right with her, and how I can win her trust back. Any advice I can get, anything I can do to make this better, I'm all ears, and would appreciate it very much.

EDIT: To explain a little, yes this is an arranged marriage type situation. As for whether I'm comfortable or not with her, emotionally speaking there is no doubt, we connect (or at least used to) completely. It's just that in our society this is the way things are before marriage, physical intimacy is not common. And she has had a few bad experiences before in this regard, so I can understand why it would be difficult for her.