Forgiving, letting go of trauma, and figuring out a friendship with my ex — any insight?

I’m in my 30s and recently (just over 4 months ago) separated from my long term (>10 years) partner due to my dishonesty and a shopping addiction I developed over the past 4 years. I even became emotionally abusive and avoidant. This avoidant behavior manifested itself in different ways. One, for example, was to not see that help was offered from my partner and instead I persisted with this addiction for 4 years lying my way around it.

I am working on myself now, seeing a therapist regularly. My addiction was easy to quit after separating and I am continuing to work on my dishonesty and avoidance as that is even deeper rooted in my childhood and sexuality and will take a lot of work.

Before I down spiralled into addiction my partner had anger management issues and they worked on it and are almost 100% better now. It is so nice to see them glow and thrive and are actually living life to their fullest. I rarely see any resemblance of their past behaviour now. However, that past behaviour was also emotionally abusive and even violent at times and it affected me a lot. This started around 3 years together when we first moved in together until about 4-5 years ago after they began therapy. I’m not sure if I ever acknowledged their progress until now after separating and I haven’t forgiven her for it. (I think I may have said it before, but I’m not sure I meant it as I still have a lot of resentment, frustration and anxiety around it).

This treatment, combined with my childhood past, led me to feel like everything I did was wrong. As a coping mechanism, I sort of shut down and became anxious. I no longer was present in the relationship and there a cycle of arguments began. They would raise issues of me not being present/invested in the relationship, which was true because my communication was non-existent as I was so anxious. Basically walking on tip-toes. I want to note that I was always a little anxious due to my childhood issues, but I think it developed to the extreme over our relationship. Also, in the first years of our relationship, this was the opposite. We were happy, open and alive. I felt the best I ever have in my life those years and felt connected to them so deeply.

The anxiety I developed in that relationship is still with me. I want to let go of it. I want to move on so I can open up again to future relationships. But I also still care about my ex and want to be friends as I consider them my best friend, the most important person in my life.

Lately we’ve been fighting, and I don’t want to sabotage this friendship over that. The arguments often start with me bringing up her past behavior, usually triggered by jealousy or unprocessed emotion, but the conversation always shifts back to my behavior, which is fair and ultimately the reason we split. It’s becoming destructive. I don’t want to keep doing that.

I want to forgive, to show that I am working on myself and taking accountability. I want to get back to a place where I’m living my life for me. Learning how to recognize what I want, what I value, and how to share that with ones close to me. Also want to note, the post highlights the negatives of our relationship which was quite bad. However, even in the bad times, we had good loving times which I look back to with so much love and joy (or sadness if I connect it with our separation).

Any tips? I guess this is mostly about dealing with anxiety from childhood and past relationship trauma, but also on forgiveness and letting go and building a new relationship. I am seeing therapist regularly, so I am partially posting to even get insights on what to bring up with them