At the risk of derailing my own thread, I think this is worth elaborating on.
For a psychologically healthy person, I agree with you MissyMay. For someone with DID...not so much. Although this was only a hypothetical explanation someone might use for why they wear a wig, there is a distinct difference between "reality" and "fact" and they do not always agree. My female alter believing she is undergoing chemo would not be "fact." It would however be her "reality." Just as her not looking at my penis, this sort of self-delusion and distortion of "fact" is how an alter maintains their "reality" of being a separate person. And it is fundamental to the way a trauma survivor's brain enabled them to cope with psychological and physical torture.
My psychologist often reminds me that not everyone needs to know everything about us. "Fact" is that as someone who has a female alter because of dissociative identity disorder from childhood truama, I had shaved my head because my male pattern baldness kept me from growing my hair into an acceptably long feminine style and it made it more convenient for my alter to wear a wig.
My female alter's entire "reality" is a fabrication, bits and pieces of what she chooses to see or not see, believe, disregard, interpret differently, or make up all together. As my System's host I would have a hard time accepting her "reality" that I was undergoing chemo. My own "reality," that I had shaved my head because it's cool for a guy, is much closer to "fact."
All that said, my "reality" that I am five different people is not "fact". I had a completely distorted "reality" of my childhood for over 40 years, refused to see the "fact" that I had been psychologically abused and raped until I had a mental breakdown in 2009. "Fact" or "reality," it is how people cope. It differs only by degree from what a psychologically healthy person would do.
Whether the glass is half full or half empty depends on where you start. Turning unpleasant reality into a truth the Self can accept is, and has always been, part of what defines my female alter. Like telling a child there is no Santa Claus, my pointing out that her "reality" is not "fact" is not only hurtful, it is disrespectful of the role she plays in my System.
I am not saying it is right or wrong, just that this is how it is. Each of us likes to believe our "reality" is based in "fact." What really matters is that our "reality" does not harm us or someone else.