I am so sorry. I cannot express the heartbreak I feel for you reading this post. I can't even imagine the pain that you are experiencing and how scary the future must seem for you. I pray that you will have the strength to hold on through this trial in your life and that one day you will be able to speak and think of your finacee without so much pain attached, but rather with the happy memories in mind.
My sincere condolances and love.