I find that to be an odd situation where you both have a delusion, and genuinely consider it to be a delusion. Like an acceptance of your diagnosis alongside a complete rejection of it?
When I was delusional I kept it to myself for fear of sounding like a nutball but also thought that secretly some other people/ everyone else was aware of the same things. Sounds a bit like your situation?
But then I only kept the delusions to myself because the voices told me to. So unlike your situation?