RP, sorry that you are having such a tough time now and over this past year. It is clear that you've worked really hard to make your relationships work and to adjust to the various developments in your life.
I wanted to second River's recommendation of Radical Acceptance; for me it had some useful ideas about adjusting to change and coping with hurts. Not all of it was my cup of tea, but I found it pretty easy to pick up what helped and let the rest of it slip away. Hopefully you could find something in it that resonated with you.