Thanks so much for your reply. I just wanted to say that my partner had surgery (in April) & the doctors have all told her that the cancer is gone & she doesn't need further treatment (no chemo or radiation). Of course A doesn't believe this & insists that the doctors are wrong. She's sure something is going to go wrong.
What you said about emotionally detach from her anger really hit home with me. It's just a lot harder said than done, especially given my dwindling self worth.