Most of the time you might have wished to know who removed you from his/her Facebook friends list. But officially there is no way to know about this. Although we all get notified about the approval of new friends requests but Facebook keeps the unfriend data hidden from us. However if you are not getting notification, when someone approves your friends request, you might have disabled it from the privacy setting.
When Someone removes or deletes you from his/her Facebook Friends list, Facebook also make an auto removal of that person from your friends list too. So neither you nor that person will be get updated about each other’s Facebook activity. But although Facebook doesn’t allow you to know those unfriended friends, but you can know about them easily with some useful tools.