It remains active even if you deactivate Facebook
How to Deactivate Your Facebook and Messenger Account
More and more people are turning away from social media, or at least Facebook. Whether you want to distance yourself from the “keeping up with the neighbors” nature of social media or you’re concerned about data privacy, sometimes it’s good to take a step back and log out.
If you have already deactivated your Facebook account, you may be surprised to learn that your Facebook Messenger account is still active. Although they both operate under Facebook, the two are considered separate services. You will need to deactivate Facebook Messenger separately.
Please note that you need to deactivate your Facebook account before you deactivate Facebook Messenger. If you haven't done so already, go ahead and deactivate Facebook. (Don't worry. Once you deactivate your account, you can come back at any time. Your data won't be gone unless you delete your account.)