Hi LeighTwo, and welcome to Sevenforums.
It seems to be a permissions problem. What are permissions? The way to control folders in the NTFS system of Windows. Where I could see them? Let's say that every folder has permissions, so to see them just follow this: Rigth clic on the folder -> Properties -> Security.
Here is an example of how it looks (My Windows is in Spanish, so where it says "Seguridad" it is "Security" for you):
As you notice, just under where it says "System" (highlighted in blue) you can see my User acount (Agustin). So what does it mean? That no other user has access to my folders (exept the System that is not a "human user"), in this case My Pictures folder. It is the case in which, altougth I tried to share files, other users won't see them. So what you should do: add your wife's user acount with the properly permissions in the security tab. Here is the way:
1) Rigth clic on the folder -> Properties -> SecurityAt this point you are able to share your folder with the user you give permissions
2) Clic on Edit ("Editar" in my Windows).
3) Clic on Add ("Agregar" in my Windows).
4) Write your wife's account in the blank place (just the name of the account; for example my account is "Agustin" so I just need to write "Agustin" in the blank place).
5) Clic "Ok" in each window to submit changes. Here is the new user show in the properties window (in my case the new user is Dana).
I read you know how to share files so try it or post back for more help.
By default, Windows give some permissions but not all of them, so if you want the other user be able to modify the contents in the shared folder or another thing that has to do with permissions, you need to mark the especific permission for it.
For example, I want that user "Dana" be able to have all the permission. So if I mark "Total Control" permission, it will mark all the permissions. Of course this must be done in the rigth colum of permissions, which is the one under where it is readable the "Allow" word ("Permitir" in my Windows).
I hope it helps you. In case of any doubt, just post back, we are here to help.