Wife on auto insurance?

NOPE, YOU CANNOT. You both have to be on the same policy unless you stop living together. Instead, buy her a car that has automatic emergency braking. It's going to be required on all new cars pretty soon anyway. https://cars.usnews.com/cars-trucks/best-cars-with...

I was unable to do this in my State.  I was asked for other licensed drivers in MY HOUSEHOLD.  That included my wife.  I could not get separate policies, because the insurance carrier thought there would be a possibility that in an emergency she would drive my vehicle.

So don't let her drive your vehicle.

Just don't let her drive your car.  Problem solved.

If you're thinking a spouse has some sort of legal right to drive your vehicle, you'd be wrong.  If you're the legal owner of a vehicle, you and you alone say who can and can't drive it.  If your wife drives your vehicle without your permission, especially after you tell her she's not allowed to drive it, she can be charged with stealing your car.  You would be required to testify at her trial, but your testimony would ensure a conviction from the judge.

Not sure what that would do to your marriage, but that's not what you asked.

So. No.  So  That won't work. So.   It is because you live in the same household and as such each of you must be reported to your respective insurance companies.  So

The "SO" generation

Do you separate all your money like roommates?

If not, what's the point.... "your" premium won't increase; her's will... and unless you keep all your money separate you are paying for it too.

That’s going to be an interesting discussion, let me make popcorn before you bring it up.