I don't see anything for you to be guilty about. If her cancer has been monitored with scans, there's no real reason for a pelvic exam, especially if she's on immunotherapy. And since the cancer had already spread outside of the vaginal cuff, a pelvic exam is definitely not sufficient.

I also spend more time than I should dreaming myself into an alternate universe where I got better, more timely treatment, and didn't have a recurrence that's incurable. But I also recognize that what I have gotten is about the best modern US medicine has to offer, so I should be appreciative.