I have seen many ways that couples coordinate their different walking levels and still manage to stay together. I have to say that I am in awe of them, because it requires a tremendous amount of patience and compromise that some hard headed people like me would find hard to exercise.
I think the tour option would be expensive and cumbersome, but it is true that these guided tours usually have a vehicle option for people who cannot walk on any given stage, so maybe they would allow a non-walker to join the group and have daily transport.
On the Frances, though, you will find that there is a very good system of bus transportation that works its way across the entire span of Camino. So one option would be for you to start out together and then your wife hops on a bus or calls a taxi to your destination. Taxis are very plentiful, and at about one euro a km, that would be much more economical than the guided tour option.
Another option I've seen is that one spouse has a car or camper van. The couple separates in the morning. Then the car driver will either drive to the day's destination and wait for the walker, or will drive to an intermediate spot and meet the walker for a break/snack/short walk. Depending on the driver's fitness level, another thing I've seen is that the driver leaves the car in the day's destination, then just starts walking "backwards" to meet the walker coming through. Although walking backwards can be tough, it's not on the
Camino Frances because of the huge quantity of people who will be coming towards the backwards walker (if you're walking in May-Sept/Oct, that is). For this option to work well, Spanish cell phones would be required, though I've seen people do this in the early 2000s without cell phones.
The only caveat I'd add is that if your wife is driving, she will not be able to stay in many of the albergues. Private albergues can take whomever they want, so you may find accommodation there. But there are so many private accommodations on the Frances that you won't have trouble at all finding private rooms for around 40-50 euros usually.
Buen camino and good luck with this, it does requie a bit more advanced planning than most other caminos, but I've seen many couples do this successfully. In fact, one option is to consider an RV rental where you could both sleep, I saw that the last time I walked on the Frances.
Laurie