Good to have your company, Lucy. Have you tried downloading free (or voluntary donation) Calibre Library software? You'll find it on
http://www.calibre-library.com. Developed by an active member here, Kovid Goyal, used by over a million folks and a swear-by at MobileRead.
I'm not a hundred percent certain about this (check with the Calibre sub forum here at MR), but you can share the Calibre Library between computers, so that may mean you and your partner can both access a version from a different machine ... I guess if it's not DRM 'protected'. Luck and best wishes. Neil