The policy comes out of the 1918 pandemic, another serious, crippling and often lethal disease 102 years ago.
Army bases were prime locations for severe breakouts due to over crowding and generally unsafe conditions. Families crowded into the hospitals and makeshift morgues, contracting and spreading the disease throughout their families and the communities.
I know you don't want to think of your wife alone, frightened, and not feeling well. Just realize there is a very good reason for this policy, just like there is a really good reason for us to mask and stand apart from people in public. She's likely to be there for a while, hospitals are overwhelmed right now and diagnosis and treatment will take longer.
Trust me, exhausted health care workers are getting this thing and some have died from it. Their families don't get special treatment, this rule is for everybody to make sure the disease doesn't spread faster than it is already spreading.
Nobody likes it, not the staff and not patients or their families. It is simply necessary at this point.