[I]s it possible to change the joists, supporting walls and foundations or who we are? What we believe, value and aspire to in life?

Yeah, and it's also possible for them to rot and collapse. The question begs for an affirmation with the end result being positive. My recent ex, who will no doubt read this at some point (Hi, honey!), seems to have responded to traumatic life events by becoming a hateful, bitter and violent human who bristles at the slightest criticism. Bristling can include a softball sized bruise delivered to the sternum of a nearby human BTW. And given the opportunity to heed red flags and advice from historical experience of basically every human ever coming out of the experience she was trying to free herself from, chose to return to the comfort and familiarity of misery rather than the scary world of change and independence, essentially dooming herself to becoming more bitter and more miserable.

My dad is a shit human being. He was maybe less shitty when he was younger. He volunteered to coach youth football when I was a kid. I don't know that he hit my mom until his late thirties. Over the course of his life his experience didn't square with his expectations and he's a crazy, broken old man now who I haven't spoken to in almost two years and the last time was pretty much serendipity so aside from one encounter it's more like 4-5.

In my experience, the capacity to change for the better is hinged on an ability to be self-critical that not all people are willing to go through. And even if a person is aware of their shortcomings the awareness itself can be cripplingly depressing. It's easier to just ignore the difficulties in life than to address them.

"When you stare into the abyss, the abyss stares back," isn't an instruction not to examine the dark parts of the world and your life. It's a statement that honest self-appraisal is fucking frightening.

Yes, most people change. No, your husband who throws you against walls is probably not going to do a 180 and become an awesome dude. The second sentence there is the honest answer people googling "Do people change?" are not truly looking for. What they're really looking for is justification for remaining in the company of toxic people. False hope is awful. It can be a punishment you give to yourself.

"Do people change?" is a charged question. It implies that we whole are either fully capable of becoming different persons or we aren't. Neither is true.

There are certain aspects of me I've observed for years to be true. They're the pillars of my personality; without it, my core idea of "self" would be entirely different. Intense curiosity is one. High sensitivity to stimuli is another. Interest in systems, lack of connection with most other human beings, intuitive grasp of modern technology, love for many kinds of music and for storytelling, hatred for brevity in the face of seeming requirement for a fuller description... All of it, and some other things, makes the most of who I am at any given moment and seems unlikely to change.

There are longer-term but not permanent qualities that make up my mindset. They're mostly negative. They can go away with time and experience, but it will take years, which would be the process of healing. Low self-esteem, depression, issues with trust and intimacy, fear of commitment... Mostly negative because circumstances sometimes open different outlook to things that can be lost, and the loss of which would be influential on whatever I do, which is not always a bad thing.

Then, there's personal growth and self-discovery. These are the changes that come with compounding experience over certain subjects and collect on top of one another, a function of the core and long-term traits, each additional experience processed through the lens of the rest of them at once. Some of those may fade in presence of other, more complex and authentic traits, or they may evolve due to psychological reaction.

My love for dubstep and hardcore electronic music when I was a teenager, for example, evolved into love for rock that I experience right now. I started appreciating certain foods more, like chicken meat, because I was much more often exposed to it in the uni. I learned that suicide is not the way for me, that I want to live more than I want my problems to go away. I grew to respect personal boundries more the more experience I had with relationships with different people. My desire for outside validation has been fading for the last couple of years and gave way to the innate honesty and sincerity that I had suppressed early in my life.

The deeper you go, the less capable of change the person becomes. My theory is that core traits are not subject to change barring harsh psychological trauma. My theory is that, at most, core traits can be suppressed by a consistent sequence of strong negative outside valuation: for example, parents can "beat out" the child's interest in the subject, but the interest can re-emerge in nurturing conditions later in life, and it may even grow as strong as it was before - because authentic experiences provide us with a strong sentiment for pursuit due to the strong positive response we get from engaging with them.

I still find it almost impossible to connect with people. It still drains me to spend time with them, to converse. But I'd grown to appreciate the depth of human nature and am eager to learn about other people, which is my way of connecting with them. That, and partaking in shared activities in a shared manner: for example, being at least decent to others when playing a multiplayer videogame together. I don't think I'm ever going to stop being somewhat aloof and distant, no matter how hard I try. It's not me. But I will pay attention if I care about someone, and I will do whatever I can to make their life better. I can give you a rundown of your circumstances and the reasons for your feelings, but don't ask me to empathize.