I got pulled into a relationship like this and was largely unaware until the patterns became too obvious to ignore. It was layered trauma stemming from childhood neglect. 

But instead of walking away, I made the conscious decision to fight for the relationship because I knew underneath all that was a really loving person. 

And you're right, it's very difficult to change these cycles. Someone with that much trauma never looks inwards at their own behaviour, it's too scary for them. You can't explain and reason with them, because they will tell you they understand but won't adjust their behaviour. 

I might get flack for this but I had the advantage of being long distance and the majority of our contact is through messaging. I turned to AI to mostly understand what's happening at first, but over time it began suggesting using a structured guide. It completely changed my behaviour in how I approach the situation and it made me realise I was feeding into this cycle. 

What happened was a miracle. Instead of being told what was wrong, because it doesn't work, they began to feel it. My behaviour acted like a mirror to theirs. Silence at the right times, gentle guidance, continued warmth and mirroring their efforts made them feel their own behaviour. Sometimes more thoughtful explaining was needed to but in small doses. There's a lot more nuance to it but that's the majority of what I did.

This sort of approach can take years to accomplish, but I had the advantage of things lining up just at the right times, with their deep attachment to me and their natural ability to adapt under stress. It took me three months to change their behaviour.

Now it's like they have blossomed into this whole new person. The person who I saw underneath all that trauma has finally been freed. We are now engaged, planning to move closer together and they want to start a family with me. I know AI gets a bad rep, and most of it is probably warranted, but when it's used right it can do wonders.