@Percypigspjs from what I've discovered (at least for me) it seems to be about immune system and nervous system regulation. I went into a state of hypervigilance. My nervous system couldn't calm down. I went into hyper-anxiety and couldn't sleep, couldn't eat, I could barely walk by the end. My body truly kept the score.
You might consider something like the Gupta program. It's £500. Some people have found it very helpful though - some for, some against.
It's about helping your body feel safe, after feeling so unsafe for a long time. In the inpatient facility we did a lot of work on breathing, understanding where anxiety comes from, depression also, calming the vagus nerve, understanding trauma, getting therapy to release it. I can completely believe your relationship did this to you. Sadly.
There is another person called Dorian Soames I have found online through Facebook. He talks about nervous system regulation a lot and works with auto-immunity. Again, I haven't used him myself. He posts his success stories but having worked with coaches in the past, I know they only post success stories, not the ones who didn't work out.
So he has some successes - but I imagine he has some failures too, again I can't vouch for him. But when we are desperate, we're ready to try anything. I may yet work with him in the future.
Aura, an app I found has been great. I try regularly now to do a guided meditation to calm my body, to feel safe. It is $65 for the year but it's helped me a lot. I also am getting help with sleep through the drugs. They've all allowed me to function again - just. I'm still weak. I can only walk for a few minutes but slowly my strength is returning. I don't feel anything like I used to. But i'm hoping with time I may.
it's shocking just how damaging these relationships are. I have a friend/ acquaintance who has been through exactly the same thing too. Her health is also shot to pieces. Her divorce has taken 2 years. He's dragged his feet at every opportunity, determined to drag her as low as possible.
Again, she was neglected in hospital, left to get herself home, get better, no help given, aggressive communication style all the time at home, walking on egg shells. When she tried to leave, he'd woo her all over again, and so the cycle started again.