This is very damaging advice. If the OP ends up on her deathbed alone, I assume you, Tutorpuzzle, will be there caring for her and holding her hand?
Of course, this is NOT to say to cling on to simply anyone just because you are ill. But cancer can be really rough on everyone and everything, including relationships.
The pain & the illness can make patients very irritable. I have been in the role of a bumbling carer for a demanding, grumpy patient as well. We are all learning.
It's probably true that the DH has been comparatively less proactive in the house like most older men. Sad truth of the era. But I also think the uncommunicated expectations are a lot here. It was smart of him to track temperatures and times for if the situation escalated IMO. I'm of course not an expert in your situation, but in his position I'm not sure I would call the hospital just yet – if diarrhoea is part of your treatment side effects or illness, why rush you into hospital which is not too safe for a chemo patient?
As for the perceived look of irritation, you say he jumped up - not trying to airily handwave your thoughts away but if he did jump up, he must still have been keen to help you.
For the other things, those were terrible on his part. He definitely needs to research more. But you only mention 2 out of probably 10 or 100 things he does for you in a day. When being a carer I also found all the things I did wrong were nitpicked on and the million things a day I did right were taken for granted.