I like to delete email from my Android to reduce memory etc. However, when I delete from the Android, the email is also deleted from the computer. It confuses my wife when I do that.
Welcome to Android Central! I assume you're using the stock Email app. Are you using the email provider's POP3 or IMAP server? If it's POP3, you should be able to specify in the incoming server settings to never delete emails on the server. Open the Email app, tap Menu>Settings, select the email account, and look for Incoming Server Settings. Select it, and look for the option to delete or keep emails on the server.