A sharp eyed colleague at work at one point noticed fingerprints bruises on my arm when I was pregnant, which was from my husband grabbing me roughly in an argument, and although I downplayed it to her face I could tell she didn’t believe my excuses and she specifically told me that domestic abuse often increases in pregnancy, that she was worried about me, and to please talk to her if I need to anytime etc.
Its good that your DD continues to work. She still has two safe spaces, two normal life contexts in which to contrast her abusive relationship experience even if this unconscious, two avenues of communication, two avenues of support, two avenues for release, two avenues for potential escape and two chunks of her life that he hasnt (yet) isolated.
Two people I know who finally left abusive relationships did it by building a confidence at work with another woman - someone who had never met the abuser and only commented independently on the objective generic actions and behaviour of abuse and coercive control (which a lot of people dont understand the details and nuance of). Maybe there isnt the tug of war feeling for the victim in these colleague relationships - they dont feel the binary dictomy of 'come home' vs 'stay with him' - basically love and judgment pulling them in both directions - and a win lose situation for either him or the family with her as the prize.
Both the women I knew left to live alone one with 5 children one with none - and it was done with a slow chipping away of seeing the light and then a slow acceptance of they need rather than the want to leave and a slow putting together of a safe exit plan (saving small amounts of money etc). There are 3 threads on here over the years - one about one woman who got small amounts of cash back on every shop, who bought all the larger sizes for her childrens school uniform, as well as extra washing powder, dishwasher tabs etc stored at a friends house so she had a financial cushion - another just the other day who has taken 7 long months to secretly find a HA prop for her DC and arrange donated furniture and will disappear once all in place - and the accounts from littleredtoothbrush who finally escaped with meticulous secret planning
Maybe this is something you could subtly engineer with her boss if there was someone new at work she slowly clicked with? Or just continue to hope that her workplace will one day present an opportunity when the stars align.
Maybe she senses your (100% justified) handwringing, desperation, judgment of him (and maybe her) from you and her family and for her this closes off communication and she is automatically subconsciously or consciously into defence mode in your company. I dont know if switching demeanor in her company would (over time) shift the emotional dynamic between you all - maybe he and her current life choices are never brought up (she already knows your views) - that the emotion when she visits is just fun and joy and ordinary life?
I say this very gently but I think your demeanor on this thread can come across as a bit blunt and harsh (I understand your emotional depletion and desperation) but if there is any of this tone sensed by your DD it would not be helping her - even if you are not speaking just demeanor. Maybe subconsciously she feels you dont 'see her' just see her always in the context of this relationship which is to you is negative and needing rescuing. This may undermine her sense of self and automony (which is already eroded by her abuser but she cant see this yet).
I have sensed a destraught nearly victim blaming despair in your words describing your daughter - which is totally undertsandable with what you have been through over the last 5 years with effectively your young teen child - she was only 14 and I doubt her emotional age and therefore capacity has grown since then - but I dont think this demeanor is helpful or will shift her perspective - more likely to entrench it.
There are chinks of light for your DD - she still comes to you - she is still working and has the potential for a trusting or influential friendship with a colleague - can you hang on to this hope and maybe try shift your mindset for your DD and intentionally aim for 'light' positive 'normal' fun interactions with your DD as a unique and celebrated self rather than the (complict?) victim in a horror story (which of course she is for outsiders looking in but she cant see this yet).
You mentioned the Drama Triangle but I wonder if you have read about the Empowerment Triangle which shifts the roles of persecutor, victim and resuer in unproductive communication dynamics to challenger, creator and coach and fosters growth and postive communications. This might be helpful for you to maybe step aside from the reactive communication you have with your DD and into a more intentional responsive one?
I also want to comment on the shouting down of suggestions of neurodiversity and depression and their managment by PP on this thread which concerns me.
There is lots of literature that evidences the greater vulnerability of neurodiverse women to abuse. The additional fact that your DD was bullied at school prior might also suggest something. Girls are hugely underdiagnosed - and without support (lifetsyle and / or medication) its no surprise their struggles with the NT world lead to depression (as would abuse on top to either any NT or ND woman). Although the abusive relationship is front and centre it wouldnt do any harm researching and reflecting whether she had any undiagnosed ND traits which, if so, might provide another avenue of how you could shift how you all communicate with her to connect more constructively.
Are you getting any professional emotional support for you and / or do you have capacity to build in additional self care to sustain yourself for the next few years whilst you watch and wait through this marathon? Can you allow yourself to hope/believe that this will have been resolved by the time she is 25 rather than today, tomorrow next week? Or is that too painful? Prepare for the worst whilst hoping for the best. If you could accept the likely long game might be another way to shift your energy.
Do you have access to any direction from any DA services who can help you navigate and sustain this connection and relationship with your child as we know in these situations the normal standard rules of life and communication just dont apply and may even be detrimental (to all of you).
Lastly after you have cared for yourself are you able to intentionally nourish and enjoy your marriage, your other DCs and your friendships without guilt? These can all take a back seat and be inadvertently blighted when they are critical for not just sustaining you day to day but bringing your some purpose, joy and relief in life.
I dont know if the core AA approach "detach with love" would help - the idea is that you recognise that you can't control or influence their choices and how you are (understandably) behaving - emotional, reactive, desparate, trying to fix - may inadvertently be enabling to the abusive relationship by bring too much of the wrong energy - fraught / intrusive - which closes her emotional space down from the other side in the tug of war. If you 'drop the rope' (deciding ahead on your own playbook of how you respond (not react) to incidents / communications with her and then get on in contructively building out your own life positively - she maybe has more emotional space to find herself, reflect and work things out for herself rather than rejecting every word that comes from your mouth.