Sam, seriously take everyone's advice, it's obviously easier said than done but we've all been there and it'll tear you apart moving on, but that's far better than prolonging it.
For reference I dragged this shit out on and off with my ex over a period of 3 years. Don't bother. It led to 3 years of depression and withdrawal, which is quite a lot of life to waste.
You'll notice that aside from everyone telling you to move on, that we're all considerably better off and happier for doing so.
Stop hurting yourself. It's over.