It is kind of hard to answer your question without a few more details.
Which email app are you currently using? (Gmail, k9, mail, etc.)
What type of accounts are you sharing? (Gmail, Yahoo, AOL, etc)
Are you using POP or IMAP?
All these questions will get you closer to the answer you are looking for.
If you are using the Gmail app on your phone and let's say, you are pushing your AOL (POP) email to your gmail account (so that you are only using one app to check both your Gmail and AOL mail), you could go into your settings on your Gmail account and set your POP account (AOL in this case), to only delete out of your Gmail.
So basically your AOL account would still have all the mail that got pushed to your phone, so if your wife is doing the same thing, then the information will still be there.
The stock app is fairly limited in options, but I know alot of people use K9, to handle all their emails and many people swear by the app and the options available.
Hope that helps.
we are using gmail and yahoo that's it and I have been using the standard mail feature that came with the phone should I try the K9 also someone told me to us POP but cannot to get it to work