Of course you do not have to take my advice but here it is anyway.
Remember however, I said you do not have to take my advice and there is a very good reason I say that, but I'll get to that later.
A driving lesson can be a very stressful experience. For both the teacher and the student. When a stranger teaches a driver-student, the stress usually culminates in the student finally passing the driving test. Good thing is that the stranger and the student-driver do not have to see each other ever again.
If you the husband, just so happenes to be the driving instructor, you may succeed in teaching your wife how to drive but in the same instance, you could very well get on her very last nerve and that could be an irreparable damage. I totally advise against that.
Taking this advice can however, prompt your wife to send you to the dog house. It's a dilemma, I know. Hence my earlier advice to proceed with caution. She's your wife. You make the call.