Unfortunately, one license only tracks emails for one email address.
It is possible to purchase another plan for a second email, if you use this on a different device or email client (Gmail vs Outlook). Simply sign up here for a free trial by following the steps in this article, and install ContactMonkey for your new device at this link. You can then upgrade your account under "Manage My Subscription" in your dashboard.
If you are using both emails within the same email client, e.g. two email addresses synced to your Outlook desktop inbox, we cannot guarantee that tracking will work properly for both emails. There will likely be interference with your tracking abilities if you try to send tracked messages from both emails.