All of the social networking sites gives you the notifications if somebody sends you a friendship request or accept your friendship request. But none of these sites, gives information if somebody unfollows you. But now, you can know that who unfollowed you on Facebook with the help of a browser extension or plugin Unfriend Finder.
If you are using Firefox browser then you need the GreaseMonkey script to use this plugin. In other browsers like Safari, Opera and Chrome, you can directly use the script. Once installed, Unfriend Finder menu comes on Facebook and see a new option in the top menu called Unfriends as shown in the image below, which will show you the number of the friends removing you from their list.
Also, you will find on the left side an another menu with more options where you can see the pending friend requests which you’ve sent to others which are not accepted yet.It will show the the ones you do not yet accepted.
As shown in the image above, it will also show that if anybody will reject your friendship request on Facebook. So, after installing Unfriend Finder, it can make you feel bad and a bit of depression too. So, use it in your own risk ;) Lol
You can download the Unfriend Finder for Facebook by visiting the http://www.unfriendfinder.fr/