This is slightly misleading, as you actually may not want to log in with your associated email address. Instead, you can use your Facebook username (if you set one up), or a mobile phone number associated with your account to log in. See: How do You Unblock Someone on Facebook
You’ll also see the steps you need to follow to remove a mobile phone number from your account on Facebook.
How to Add Mobile Number to your account on Facebook
To add a new mobile phone to your Facebook account, do the following;
1. Log into your Facebook account
2. Click on the account settings at the top right corner of any Facebook page
3. Next, click settings from the drop-down menu
4. Click mobile at the left column of the new page that appears
5. You’ll need to click Add another mobile phone number to activate a new number.
6. Type your mobile phone number and click Continue.
See: Facebook: How Do I Deactivate My Account Temporarily?
How to remove a mobile number from your account on Facebook
To remove a cell phone number from your account on Facebook, do the following;
Follow the steps on how to add a mobile phone number to your account above and then click Remove from your account next to any number you’d like to remove.
How to add or remove an email from your account on Facebook
It’s recommended you add an email address to your account so that in case you lose your mobile number, you can use email to access Facebook.
Bear in mind that Facebook will send you a confirmation email when you add a new email to your account. You’ll need to click the link in that email to confirm that you want this email added to your Facebook account.
To add email to your account on Facebook, do the following;
1. Log into your Facebook account if you’ve not done that already.
2. Click on the account settings at the top right corner of any Facebook page
3. Select settings from the drop-down menu
4. Next, navigate to the left column of the new page that displays and click Contact in the General tab.
5. Click Add another email or mobile number to add a new email to your account. Click Remove to delete an email from your account instead.
6. Click Add or Save Changes.
Note that you will need to re-enter your Facebook password and click Submit before a new email is added to your account.