My wife who I have been with for 14 years of my 30 on earth is in bed right now and I am damn near crying reading about the situation you and your wife are in, wanting to go in and wake her up to tell her how much I love her. I feel for you and absolutely wish for a speedy recovery and for you to stay the positive and strong husband she needs right now.
I remember one time I was worried about something, which is not normal for me, my wife stopped, looked at me and began crying and said "your the calm one, you tell me it's all going to be okay".
Just try to be her calm one and reassure her it will be okay, that is your purpose on earth until she is in remission.