Frankly, I think you need to look to the online DID community for answers, I doubt you’ll find answers here. I’m 35 years into a recovery with SZA and I’ve spent time researching DID and I have a very hard time making sense of it all, yet I understand the dynamics of SZ fairly well.
There are some people where DID is comorbid with other SMI. The more I learn about it, the more I feel like a cis gendered person grappling with understanding the LBGTQ+ Community especially the intricacies of trans and gender non binary folks. There’s a ton of lingo and complex individualistic inner relationships of alters. It seems no two DXes are alike. There are a number of DID folks on YouTube and that may be a place to start.
Best I can tell this is more complex than simple anosognosia, a sort of selective amnesia between alters in many cases. Finding treatment in the US can prove difficult as many psychiatrists were initially taught that DID was a hoax, and can be very skeptical of such a DX. False or coached memory syndromes were common in some early treatments which led to discrediting many accounts. My psychiatrist admits that DID exists, but is very skeptical and has said frankly that he thinks most psychiatrists would try to over medicate to suppress symptoms than try to get suffers to adapt or integrate.
One thing you may gain from this forum is to learn from the many people here who live with spouses or partners with SZ or other SMI. Regardless of DX or symptoms, there’s a personal emotional toll to be paid. Some advocate running, not walking, far far away from a relationship with sufferers, yet others advocate learning as much as possible and sticking it out. Since you seem to be asking for practical answers to specific questions that only someone with a DX could understand, I think you’d be better off in a DID forum. Good Luck.