So sorry to hear of what you're going through. It's hard to function, let alone mend from a broken relationship when you're screaming inside, and feeling like your stomach is crawling out your throat all the time.
Obviously you're doing what you can to handle things, even if it's pretty tough going at present. I wonder if it's worth finding something else to try and focus on, to distract you a bit and to help you feel there's stuff you can achieve which makes you feel alive again, and of worth? It's easy to get caught up in continually re-hashing scenarios, and focussing on negatives, which only drags you dow further. Self-perpetuating cycle.
What ambitions do you have? What is somthing you'd love to do? What sounds like a fun activity that you might not ever try in normal circumstances? Maybe it's time for some adventure in your life, so that can help you mark a new starting point? It won't stop the pain, but it may help change your focus. Can be a useful coping strategy.
When my dad died, after a very painful battle with cancer, I was devestated. Words can't describe how the pain felt, and I wasn't coping at all. I ended up making the decision to try and "jerk" myself out of that state by jumping out of a plane. It was a very conscious decision to create a recovery point for myself - to try and change the way I was feeling. It did work, though it wasn't a cure-all, by any means. I think taking control of your own destiny can be a very strong statement to yourself, and that's a good start.
Sending lots of good thoughts your way, and hoping for healing after what you've been through.