Query mail logs for xp_sendmail
Using xp_sendmail I believe the only history you will find is:


Critical events that were severe enough to warrant an entry into SQL Server's error log. This does not include things like bounces, undeliverables, malformed addresses, etc.
The history of the e-mail account that is used to start Outlook on the server. So for example you will see sent items there, and bounces / undeliverables in their inbox (if the account accepts incoming mail). This will depend, of course, on what's backing that account - e.g. Exchange. 


There are many reasons this feature was deprecated in favor of Database Mail. Unfortunately you need to upgrade to take advantage of better functionality.