And rather than trying to determine exactly who is the most to blame, just remove yourself from the situation. Knowing who is most to blame won't resolve the situation anyway.
I had a horribly disturbing nightmare when I was still with my x. I dreamt I killed somebody. In the dream I was a janitor, dressed in blue overalls, and I was cleaning the platform of Dun Laoghaire station I stabbed a man in a suit in my dream. Then I ran away. In the dream I had 'got away with it' but I was wondering why I'd killed somebody and I felt so crushed by the guilt.
It was only a while later that I made sense of the dream, and what all the different things represented.
But your subconscious is trying to tell you something, and you are NOT LISTENING TO YOUR OWN VOICES< TO YOUR OWN REASON!!!
Remove yourself from this relationship and the nightmares will stop.
PS, I also had a dream that I was sinking to the bottom of the sea in a bell shaped submarine. The pressure eventually became more and more intolerable, and then I woke up in a sweat. I was drowing in my dream, drowning in real life too, and my dreams were telling me what I couldn't seem to face up to.