To me it seems there are two issues here:
you would rather not drive, either all the time, or long distances, which probably entail using the motorway.
You are well within your rights to dislike driving, and to stop doing so, if it is causing you anxiety. And, if you feel you are no longer driving safely you MUST stop.
You have made arrangements for someone else to drive your husband to hospital, which brings me to the second issue:
Your husband saying you should be taking him. This to me sounds like the typical male way of saying he would like you to go with him to the hospital because like most of us, but no man will admit this, he is nervous of the operation.
So ask the driver if you can come along too, as others have suggested. If your husband is being discharged the same day, and whatever others think this is common practice now for knee and hip replacements, does this mean the driver will be hanging around waiting for him to be out of the recovery room and ready to go home?
If so, obviously you must go, and take the poor driver out for lunch or whatever meal is appropriate. I can't imagine anyone wanting to drive 120 miles back and forth to a hospital twice in one day!
If your husband will be sent home by ambulance or some kind of taxi service paid wholly or partly by the NHS, phone and ask if they are willing to transport you as well as him. If the are, you go too, taking a good book or your knitting with you for the time the op. plus recovery plus the surgeon getting up to see and discharge your husband takes.
If rules do not allow them to transport you at all, or only if you pay, then you have a reason for remaining at home that your husband may be cross with "the system" about, but can hardly blame you for.
I hope everything goes well, and he makes a speedy recovery.