In hindsight the clues were there but I put everything down to her divorce, a bereavement, stress, pregnancy, PMS, PND you name it.
The last ten years have been tough, rreally tough. The more that is expected of her, the more she has retreated and difficult she has become.
About a year my SIL found an article on Demand Avoidance and it shook my world. It explained DW to a tee, but it also means that this it, especially as she will never likely accept any chance that she may be on the spectrum. This despite DS ASC and half her family being ND.
Can I accept this forever? I don't know, but I'll do what I have to reduce the pressure until the kids have left home.