Hey mate. I can empathise with feeling rock F@@king bottom and looking for an “out” if only for a rest from feeling so utterly broken. It’s a terrible terrible place to be, but your not alone, and you can and will get through this ( honestly)
So pleased you’ve reached out and got professional help, that’s a huge, and brave step to take, of everything I found that the talking therapy worked wonders for me.
Please Please Please be kind to yourself, you’ve had a difficult relationship ( from what I’ve read here) which has ground you down, then you’ve had a really important relationtionship end with no warning, only to find that another person was on the scene. That’s a shed load to deal with, you’re going to be upset, angry, desperate and not know which way is up. It’s ok to feel as you are, you need to hold on to the thoughts that this will pass, there is a way out.
As I said be kind to yourself, eat well, even if you don’t feel like it, stay off the bottle, take the help, get out of the house even for a walk around the block.
You can and I’ll get through this fella, it will be a hard old slog, you’ll have peaks and dips along the way but you will come through this. Your not alone in going through these feelings mate,and you will push through this.
I’ve popped a link below, it’s only short but I found it good as I started to recover.
Take care mate, be kind to yourself, this will pass these feelings will go away, you will get past this honestly, regardless of how impossible that seems right now.