In order to keep track of emails you send to guests, as a standard setting we bcc your administrator email on all correspondence.
If you find this clutters your inbox, you can turn the function off.
Go to Settings > Account > Outgoing Email and scroll down to the 'Send Copies' section. If the function is turned on, you will see your email address in the Bcc Email Address box. Just delete your email address and then press save to turn the function off. You can always turn it back on by re-entering your email address into the same box and saving.