Husband has mild cirrhosis, no ascites or portal hypertension. said for the last week has had black poop. wont go to the doctor. what should i do?

Respect this: There is nothing you can do to force another person to seek or accept health care. This may be trivial or may be very serious. If he becomes gravely ill, call an ambulance and in the absence of an advance directive refusing care, his life can probably be saved. But do not nag. Your relationship is much more important than being right, even about this. Best wishes.