Your situation is similar to what mine was about seven years ago, the difference being that I was the Witness. I met a great girl: very intelligent with a real desire for knowledge on almost any subject. I got her to agree to a "Bible study" with me and even got her attending meetings for a few months but I could see that it was killing her spirit.
We had fallen in love by that time and planned to marry in the future but whenever she expressed doubts about the religion we would argue and as I had the stronger character she usually relented. I had told her that I would marry her whether she joined the Witnesses or not but I found that I just could not stop trying to convert her. Wing Comander is absolutely right: she is trying to manipulate you and I should know because I did it myself (much to my shame).
It still brings tears to my eyes when I see her face in my mind and I remember her telling me how she could not understand how I could go from being so tender, romantic and loving to being so angry and unreasonable whenever she would say that she could not accept my religion. It was crazy; I knew I was damaging our relationship but I just could not help myself...afetr all, I thought that I was aiding her in her salvation.
There were other factors (one particularly large one outside of our control) involved but my constant preaching and resentment crushed our love and I never heard from her again.
Ultimately Teel you have to be true to yourself and not let your spirit be crushed by someone else. She probably loves you as I loved my darling but from what you are describing the organisation has a hold on her like it did on me. I am no psychologist but I suspect that her loyalty to the organisation will poison your relationship and will likely cause a great deal of pain to both of you. Difficult though it may be for you to see now, clouds often have a silver lining and in my case I was able to begin questioning the organisation a lot more after my heartbreak and now I find myself mentally free and in the process of fading. Who knows? This may be one of the stages of her own exit.
I hope this gives a little food for thought and will enable you to get a glimplse into "the other" mindset (she is possibly experiencing a dreadful clash within herself, as I did, so a lot of patience and love will be needed if you plan to try and work things out). What you do is ultimately up to you and I hope that you can salvage things. I will pray for you.
Sorry for the long post.