I found that early in the lockdown I got nervous of driving simply because I got out of the habit. In addition, with roads being quieter I encountered some really bad driving which made me even more nervous. Now, although I'm not driving every day, I'm going out a few times a week, not just once for essentials, and my nerves are settling. I've been driving daily for over 45 years so it came as a bit of a shock, but it is passing. I think the 'use it or lose it' applies here. Try to do small journeys regularly and offer to drive even if your partner could do it. I think your confidence will return.
When I was married my husband always drove if we went out together. He only let me drive on the way home if he'd had a few drinks or on a long journey if he got tired! When we first split up I found long journeys quite scary although short ones were no problem as I still drove daily in the locality. In the end I just had to make myself do it otherwise I'd have missed out on so much as my children both live hundreds of miles away.
I do use the train to visit my DD as she is over 400 miles away and when I'm there she has a car we can use and public transport there is brilliant, but I always drive to see DS as I would need to use taxis as well as a train and he doesn't drive himself although his wife does.
I was looking forward to getting my bus pass later this year as I thought I could maybe use the car less, but the bus services have been reduced so much I don't think it will be of much benefit, so being able to drive is an absolute necessity for me. I think it is for many people these days unless you live in a city where public transport is reasonable.