Emotionally dysregulated brains

I had my first session with my counselor last night. She seems lovely and so far the rapport is pretty good. I have another appointment scheduled for next week. She doubts that a diagnosis of borderline personality disorder fits me. Her thoughts are that two divorces simply aren't enough damage to warrant the diagnosis. Apparently people who suffer from borderline will sabotage perfectly happy situations. I can see her point. I haven't knowingly sabotaged anyone. It may not be the right diagnosis for me, but I do identify with many aspects of it.
She posited that perhaps I'm dealing with a lot of grief from life events and early trauma and we are going to try internal family systems therapy. I'm interested in trying it and seeing what I can learn. The work begins next week. In the meantime I hope to lay low and not cause a row (British English usage).
One thing that is a through line in my history is my own emotional dysregulation when someone is reacting negatively to me. Whether it is a student who is silently contemptuous, a partner or child who is angry with me, or a frazzled service worker who is rude to me, I tend to become dysregulated very quickly. Once I am dysregulated, no matter how hard I try to solve the issue calmly, everything falls apart. Social evaluative threat, social pressure to perform, seeing a loved one suffer emotionally and interpersonal strife send me into fright, flight and fight modes. The amygdala may have evolved to help us save ourselves, but it surely doesn't seem to help much in relationship with others. This has led me to keep my people circle very small and unfortunately, I have alienated or had to sever relationships that matter to me, simply because I was too overwhelmed and couldn't cope or because the other party couldn't cope with me any longer.
This is only a part of my neurosis, but it is a major part. I hope to learn how to regulate better and how to communicate with others better. Communication wasn't taught in my family experience. My house was mostly silent. If I cried I was sent to my room. I didn't dare get angry or sass back. I would be spanked or worse.
My mom used to lament that we didn't talk as a family. What she meant of course, was that we didn't share deeply. We all learned various techniques of shutting down when the emotional air became thick. My dad taught us that. His mom or dad taught him. Who knows where it started, but for at least a few generations this mode of frozen avoidance has persisted. Some of my brothers can disagree with each other, then laugh it off, but mostly I'm just not familiar with people talking about grief, pain, injustice or hurt feelings. My sister played the "glad game" that she learned from the actress Hailey Mills in Pollyanna.
Either by shutting down, or changing the subject, or removing ourselves from the situation my siblings ensured - just as our father taught us - to keep the conversation on the surface level. We didn't have fun together - no camping trips or shared familial experiences except for the Christmas monopoly game for a couple of years. The only levity was our brother Joe, who provided good stories, laughs and an openness for others. But he could also be cantankerous and irritable. I guess he was a human being. And, of course, my saintly sister. Always warm and open to others, playing the glad game for 72 years until she just couldn't anymore. Now, what remains of us just don't talk to each other very much.
Of course, I can't go around expecting no one to become angry or displeased with me. A life free of criticism is delusion. Human beings are going to annoy each other, hurt each other and disappoint each other. But there needs to be room for healthy and restorative repair. These are skills I don't know.
What tends to happen is that after repair in my experience is that we don't forget what happened. So, when it happens again people become even more estranged from each other. Trust erodes and then, I'm alone and afraid to interact with anyone. This is, of course, unsustainable. I don't want to lose my children, I want to grow closer to them and watch our love for each other grow as they begin their own lives. I want to have deep friendships and I need to work so I have to interact with people. I pray for a mind that at some point is not so hostile to itself.