2 ipads 1 account how not to show wifes purchases on mine

If you are using the same account then they any apps that she purchases will show in the Purchased tab in the App Store app on your iPad (and similarly music, films and TV shows will show in the Purchased tab in the iTunes Store app). Whilst you share the same account then only to stop them showing is to hide them via a computer's iTunes, which will also hide them from Purchased on her iPad (so won't show there if she wants to redownload them) : Hide and unhide purchases in the iTunes Store - Apple Support (on the current version of iTunes the 'x' is invisible, but clicking on the top left corner of an app where it should be should still hide it)

If you mean that they are automatically downloading on your iPad then turn off 'automatic downloads' in Settings > iTunes & App Store on your iPad - that will stop purchases made on that account on a different device or computer automatically downloading on it.

Why doesn't she simply create her own account? Back up her iPad, wipe it, remove your iCloud credentials, and then restore from the previous back-up. If that doesn't work, remove your credentials as suggested, and then she starts again with a "clean" iPad.