Hi, and welcome to the board.
I'm so sorry to hear your story; I'm afraid that many JWs and ex-JWs have reacted this way to the terrorist attacks. Others who are more knowledable than me can take on the subject of peace and security. I'd like to respond to your post in general.
I left the Witnesses way back in 1984; I had a lot of doubts and although I hadn't done any deep studying, I knew things weren't right and didn't make sense. But I had, in the back of my mind, the worry that I'd done the wrong thing, that maybe the Witnesses were right and that my kids would die at Armageddon because of my decision. Do you know what finally put those thoughts to rest for me? (And for many other ex-JWs?) Reading Ray Franz's two books: Crisis of Consience and In Search of Christian Freedom. Ray goes into great detail about JW teachings and the way the organization is run. After reading two books, I don't see how your fiance could still believe the Witnesses are right about the Armageddon predictions. Please try to get him to read the books. You can order them from several different places, including FreeMinds.org and Amazon.
I wish you luck, and I hope you can convince your fiance that the Witnesses are wrong, wrong, wrong about this--both for your sake and for his.
Best wishes,
Julie