I have come to this thread countless times and clicked back out without responding - it's been difficult; you'll see why below.
I think that you have a compound problem.
First, this board is full of men complaining about their wives shutting down sexually in some form or maybe even totally. So, there's that (and plenty of good reading for you as you rummage around on the Board).
But more importantly, there is what I think is PTSD. Let me state why I might say that.
Over a decade ago, I received a phone call from a doctor who told me, and I quote "you have an uncurable, untreatable Cancer called XYZ". (He didn't say incurable, he said uncurable...). It was as if a hammer had hit me and pounded me into the earth to about my knees with one blow.
Your wife went through the same type of process. It sounds like, from your posts, that the results have been good - Thank The Lord - and, for my case, prayers - thousands upon thousands of them - kicked in and I, too, am in the "cured" status and not even in the follow-up check routine, but, rather, kicked back out into the general population where we all wait for the next shoe to drop.
But, the immediate aftermath of such a pronouncement sends the mind to places that it has never been before (and to which you never want it to go again). I promise you that your wife went through some form of that. 'Will I get to see my kids grow up, will I ever see the days get long again, will I ever see another spring, fall, summer, whatever?
And, then, there are the strange ones. I remember thinking - more to the point of this Board - "I'm not ready to die, I haven't had enough sex yet." And the one where I thought "I've not gotten to enjoy all the Classic Rock that I want to hear".
Crazy stuff, but the mind goes nuts, especially during those early stages when it is all "unknown" out there in front of you.
Your wife, I promise, went through all that in some form or fashion.
Fast forward almost two decades to today. When we are watching some type of TV show like "The Voice" or "American Idol" or the like where they give a background package on the candidate or the candidate's loved ones where Cancer is involved, and especially where there has been success, DW knows to reach over and grab a tissue and hand it to me because she knows that I am sitting there silently bawling my eyes out. It is part of my PTSD reaction to all that I went through.
So, I related all that personal stuff to make the point that you are dealing with something much more deep and maybe much worse than the common sexual issues that we commonly see on this board.
Now, others smarter than me, and maybe more specifically trained than me - my training is not in this area - will have to guide you as to how to get her help for the latter (the PTSD) which might or might not help with the former (her seeming attitude about sex overall).
Yours is a tough one. You have my prayers.
PS: and as a PS, I'm sure that all the other Cancer survivors (or sufferers) on the Board will second this; I now know how to pray to our God concerning Cancer much differently and in a way that I never imagined before - so I'm lifting those up for you and your DW.