I don't think you have a delimma at all, if she doesn't want to pay for them she doesn't get the files. If a customer asks for the original jpegs (I very rarely shoot RAW) and is willing to pay my price, they can have them.
Exactly. This will I think become the model for a lot of professional photography going forward.
In the film era, most professional (non-publishing related) photography sales were print driven. A lot of people are trying to hold on to this model.
Now clients want full resolution digital images to use for all sorts of end purposes. Instead of fighting it, use it. Figure out the most you are likely to be able to sell the prints to the client for and subtract out the cost of the printing. Now double that figure and you have a reasonable price for what amounts to selling the negatives.
It's win-win. You get more revenue per job shot and the client gets broader use.