I know you miss your feisty anger, but there's nothing to say you have to lose your defiance. Personally, I LOVE defiance, I find it incredibly motivating. :)
So you won't lower yourself to email his work BUT you can still plot revenge... The really awesome FUCK YOU, I'LL SHOW YOU type of revenge thats really productive. Plot your total plan for world domination without him. Plan next year, how you're going to look gorgeous, do amazingly well at your job, live in a fab house, travel, save a fortune and just generally be FUCK OFF AWESOME. This is your chance to concentrate on YOU and how FABULOUS your life can be now. You show him! You totally ROCK your own life now and he'll hear about it and feel like a COMPLETE TWAT.
My favourite book ever is a trashy novel by Sidney Sheldon called "The Other Side of Midnight". The heroine, Noelle, gets jilted on her wedding day by a pilot, Larry. She responds by turning herself into a world famous model and actress, posing for publicity shots and doing endless films JUST because she lives for the day that Larry sees her successful face staring at him from a magazine and thinks, oh bugger, look what I missed.
It's not really a healthy story (!!) but she is BLOODY AWESOME in it and it's a lot more productive than crying in your pjs, sobbing over his facebook page and getting fat on ice-cream and gin (the other traditional break-up cures). :)
So, can you set a plan for a wonderful 2015? Just to lift your spirits a bit and keep that defiance going?