Facebook is borderline scammy with it's practices. I few months ago I made a mistake of installing Facebook Messenger (which is now only called "Messenger" in the Play Store) to communicate with a friend who was in town. To use the app I had to verify my phone number. When my friend left town, I removed the app. To my surprise, I kept receiving notifications from an app called "Messenger" which is not accidentally also how the SMS app in stock android is named.
There is no way to disable it from my phone and after 15 minutes of looking around I could not find a way to fully disable it in the browser either. I could remove my phone number from the account entirely, but then I would not be able to use sms to recover my account. The best I could do was to set the maximum number of messages to 1 per day.
That, and you also can't change your relationship status to married retroactively without Facebook notifying every person in your contact list.
That, and you also can't change your relationship status to married retroactively without Facebook notifying every person in your contact list.