I was interested in the last line of your post -- that you were afraid of her repercussions. Is that what you are really afraid of? It's okay if you are, just trying to figure out where you are at with this.
If you just want to not hurt her, the best thing to do is to end it. She will need closure though. I would suggest that you tell her something like that you would like to see other people or something like that so that she figures there might still be hope. I only say this because as a woman, we live on hope like this. Soon, she will become bored with your lack of attention, especially since you are far away, and meet someone new. Yes, I know, but it does happen.
so, here's my advice, the best thing would be is to just be honest and tell her, but if you are afraid that it won't sink in or that she will want to retaliate then just cool it off and let it die a kind of natural death, but DO NOT see her or give her any real reason for her to have hope. Just allow her to play it out. She'll get tired of you starving her.