I have 3 DS, aged 12, 10 and 6. It's the eldest who has OCD symptoms, it happens mainly at bed time and includes hearing voices. I know it is caused by the strain of my relationship with DH and he is on waiting list for treatment, like your DD. He (DS) is going through puberty and clashing with his Dad a lot but whenever I defend him, DD has a million justifications for his appalling behaviour. I am haunted by the story of my SIL's sister; she took 4 years to get away and her 14 year old daughter now has severe depression, self-harms and had to be sectioned last Xmas. All triggered by her narcissistic father's shitty behaviour. I don't want that for my DS and that's why I have to go now. DS has also started noticing the way I'm being treated and telling me it 'could be abuse' based on PSHE lessons at school, I think. I'm also extremely worried he could emulate his fathers behaviour one day; he has no other male role model after all. If my DS behaved the way my DH behaves to a future wife/ girlfriend I would be furious and tell her to run for the hills.
I don't know how I'm going to leave yet. Last year I got a PT job and that's really boosted my self esteem. I'm seeing a solicitor today, one who specialises in abusive men, and I'm seeing Women's Aid again next week to 'make my plan'. Last year when i got rid of him for 3 months, I didn't realise how manipulative he'd be; anger, suicide threats, threats to cut contact with the DCs. I didn't have enough resilience to cope with it and took him back, so this time I'm making sure I have a plan and lots of support. I'll also have to go NC, to avoid the abuse via text I got last time. It's much harder to leave than anyone realises, but as soon as he was gone the DCs were all so much better. My youngest one cried and missed him, but he didn't really understand what was happening and is much more anxious now. Also, he has been hit twice by DH, hard enough to leave a handprint on his leg and that's just so wrong it makes me angry to type it
Hope you get enough strength to leave; remember, it's about what's best for you and DCs. Try to call Women's Aid. I think that, like me, you need someone independent to tell you it's abuse and that no one deserves the treatment you're getting, however untidy.
BTW, I have lots of 'faults' too many to mention here, but it's just a way to put me down