Think about this like this

When anything happen do you blame yourself? Why do you do so?

The leaving of a person is not your fault it is the person's own choice that have attracted it to themselves. when they blame you for anything it's because they need an outlet to release their own guilt. not you who is guilty.
there is a very clear definition when you are wrong. when you see clearly then you know whether you are wrong or right. when you are wrong, no matter if the person accept or not apologize properly. and IF you are not wrong in certain situation. there's no reason to argue because of fear or competition. because there are none. the world is abundance and there is no competition. and the fear you felt is merely in your own head. blaming and finger point are merely the effect of the ego and pride nothing more and nothing less. If you star reacting to accuses true or false it maybe you are merely standing as low os the accuser and have a meaningless fight. how you know? ever feel any good after even you so-called "win the battle"? No. there you know then no good in argueing.
So what to do? just ignore the arguement. see the truth. if you are wrong then apologize. if you are right then let it be and move on to next item.

Another example is you get a raise, you are not stepping on any corpes when it happen. they are merely there because of the person own decision and action. non of it is our own decision. the only thing that's happening here is that the effect just happen to happen to you of benifits and you gain it either by your own effort and decision or attraction.

How if you are fired? then it's even more reason to examine yourself. if it's something that's your wrong doing then apologize. if it's jealousy, then see why the person reacted in such a way. if you can't change yourself to accomodate any of the situation that arises then It may have meant that you are meant to leave. Be grateful of what's happening. there's no reason to be afraid go out into the world bravely and with a little bit of effort and less complaining, you'll find you'll find a small spark of life and lead your life into the new chapter of your life. Change is not bad. It's merely a part of the interesting life we lead.

See Thy self and Own Thy self. for none could ever conquer nor destruct thee but thyself. May All of you gain happiness and Good wishes.