My spouse & I do the same—to protect ourselves and each other. Unfortunately, people are pretty sexist in that "I'm protecting my wife" is somewhat better accepted (albeit in a condescendingly indulgent way) than "I'm protecting myself". I'm now using the former reason increasingly often.
You should be allowed to protect yourself, too. But also a lot of women have reported that pretending they are caring for an elderly relative gets them less abuse for masking than acknowledging their own vulnerability. People judge the vulnerable, not those caring for them. It’s basic ableism
To care for a chronically ill person is seen as a noble sacrifice. To be a chronically ill person is to be seen as a burden, a sacrifice other people have to make
I think we would both have a rough time with Covid—she's older but I have more chronic illnesses.