IMHO there is no point in striking back at an N--they will never get it anyway and at the first opportunity they will turn it back on you to punish you. We already know they will never change.  Don't waste your valuable time and energy--turn it inward to motivate yourself to move on to something better.

 

Here's the worst thing I did to my XN:

 

I left him......I started my life over.........and I'm profoundly happy without him. 

 

 

I recommend it highly.