Within Teamwork.com, you can add alternative email addresses to your profile.
Click your profile avatar in the bottom left of your site and select Edit my details from the pop-out menu.
In the user details modal, go to the Details tab and click the Add More Details option at the bottom of the tab.
You can then enter up to three alternative email addresses in the available fields. Click Update to save the changes.
For more information, see: Viewing All Items in Your Profile