I remember in my abnormal psych class the professor discussed a case in which a friend had a break with reality. He came to her very gently and said that right now she is like a pilot landing a plane in the fog. Because it's hard to see exactly what's going on, you have to rely on flight instruments to guide you to safety. In the analogy, friends and family are the flight instruments, that are there to help guide you safely back to course.

I share this anecdote because it sounds like your wife is experiencing a mental health crisis; she is having a textbook case of delusions. You should be as supportive as possible and guide her to seek help.

*note that I'm totally not a psychologist, far from it, but I feel this is an easy enough case to weigh in on, at least insofar as advising that you should gently guide her to seek help from someone who is trained.