It is very easy, you will most likely end up walking separately at times, but you will have all day together once you get to your destination at the end of each day.
From Ponferrada it is about 120 miles, 9 days or so, if you have 15 days, you will have plenty of time to walk at a leisurely pace. Also, that part of the camino is fairly crowded, so if your wife is afraid of walking on her own, that might not be an issue.
In any case, I am sure you will find your own paces and compromise on things; personallyl, I would HATE walking with a photographer who stops for minutes just for the sake of taking a picture, it would wreck my nerves.
Whatever you end up doing, buen camino, amigo!