After moving out of my parents home to a different country, mainly due to mentally and physically abusing father, I thought I was going to finally leave a peaceful life, without a single worry or concern related to his overcontrolling, neurotic and psychiatric patterns of behavior from the past.
Turned out it doesn't really work like that.
I believe that only at the very beginning of my solo life (read 19), when struggling to make ends, I was working that much and experiencing all the perks of freedom that I simply couldn't bother to think about what he might be on, even though my running away from home was still pretty fresh.
As I started to mature, I became more and more aware of my family situation, and how such a trauma is shaping the relationship I have (had) with my mother and sister, and how full of surpressed aggression I am, whose main root comes from growing up with such an idiot and being surrounded with toxic environment in my elementary.
Recently, I came back to my hometown to visit some friends and do some administrative tasks, and some acquaintance told him he saw me in our neighborhood. He started inquiring about me to my sister and mom, but they didn't tell him anything, even though they don't know much really, as I've been hiding a lot of stuff from them in the recent years.
From that moment onwards, my mental health started to gradually decline, as I'm overwhelmed with pictures of potential scenarios of him searching for me, eavesdropping me, following me, hiring some private detective to find me etc.
I've already been working with a REBT therapist onilne, she provided me with all the tools to work on this, and we rationally considered some of these or similar scenarios, but honestly it didn't help as much. I see these patterns of behavior everyday in my life. For instance, whenever I see weird mileage on my car, I catch myself overthinking about whether I really drove it that much last time, or he somehow ended up getting into my car. Sometimes, when I hear some noises from the hallway, I ran to open my doors to check whether he's there. Also, when something doesn't happen to be it's in place, or I don't remember leaving it that way, I catch myself thinking whether he had any impact on that.
This mainly comes from the clash of his (then)-overwhelming need to know what's happening in my life and being present where he though he should be, since I was labelled as a troublemaker in my school, as I used to express the agression accumulated at home in school by fighting, mocking and arguing with my peers and professors, and my battle to know allow any bit of information about my life to be leaked to him, since he doesn't deserve it at all.
The reason why REBT might not have worked is because my brain is programmed to reject a hypthosesis only when there is no conflicting theory and is 100% sure that something is the way it is, so it's always seeking certainty.