Apple Account problem

I've been a Mac used forever. My wife recently saw the "Light" But, she started out using my apple account. Now her iPhone and iPad calendars, her purchases and other stuff are showing up on my computers.
How does she get her own account? When I try to set up her account it says that that email address is already in use.

This has also screwed up my auto fill. Now her name and address are in my auto fill.
This has all happened since I upgraded to Maverick.
Thanks for any help.

My wife and I use the same Apple ID on our computers and iDevices for apps and iTunes so that we're not purchasing anything twice and have the ability to download and install each other's purchases if we so desire.

When my wife decided to start using some of the other sync facilities - signed her up for her own iCloud ID.

This keeps my email/calendars etc on the original iCloud ID (which is the same as the Apple ID) and syncs her email/contacts/calendars with her iCloud ID.

(Since she's the late arrival - she gets to keep up with 2 IDs. However, once they're entered on all the devices, there's not much to it except keeping track of the username/password.)