Through mom's recovery I've gotten mad at the weirdest times. One of the angriest I got was when, after going through so much and finally being at home with me, mom complained of chest pains. Yes, chest pains, and I was annoyed. Not at her condition but at her trying to be polite about it. She didn't want to bother me because she knew I was on a work deadline, Yet she knew she needed to go to the hospital. Getting an answer was maddening. Literally.
She gets angry, too. Mostly at not being able to do what she wants. So innocent inanimate objects, like an unreachable pan, or a non-working bulb, become enemies.
Mercifully, we haven't been getting angry at the same time so the other person is able to be a calm voice. That's good because we can't afford to be mad. Even if we have another 30 years together, time is short. We can work out whatever it is.
Whatever it is, get over it. Quick. "At least you have your health" is a real perspective.