Codependency and the "angry god"

Hello, I'm new to this forum. I figured online support is better than nothing, since my community doesn't really provide anger management groups or courses regularly. I feel like I really need help.

This is a very complicated mess, so bear with me. Please ask for details if the picture I'm drawing here doesn't add up.

I come from a toxic home. My mother was the very image of codependency, complete enabler with a lot of resentment right under her skin. My father was (is) an alcoholic who didn't know how to be a good husband or a father to me and my sister. Me and my sister learned to push our needs aside quite early on and I personally have a lot of anger issues because of this.

I don't explode, I don't act violently (I used to when I was a teenager), I don't damage property. Surprisingly many people consider me to be a very warm, kind and generous person with a good heart. My ex said I'm the kindest person he's met and no one has treated him as good as I did. Two months after our meager 6 month relationship ended, I still have immense anger towards him. Just today I cut all ties, revealing that I have the kind of anger that stemmed from his emotional neglect (he's got BPD), feeling humiliated and not having my needs met. He didn't agree.

The "angry god" in the subject is referring to the state I'm in when I feel intense anger. It's all about swollen ego and this bitter, FALSE sense of self-entitlement that usually occurs when I feel that I have been wronged, that my needs have been ignored. There's no doubt that state of anger has a narcissistic flare to it, after all it's about MY needs, I have been wronged etc. A legacy from my childhood home, something 11 years of therapy for depression didn't wipe out.

In order to fight the anger I need to learn how to take responsibility for both fulfilling my own needs and not accusing others for my anger. No one knows my needs better than I do and no one can happily be with me if I don't voice my needs and give these people an opportunity to be a good partner, friend, co-worker etc. if they so wish. It would make me so much better person to be with! The anger just grows and grows because I keep it inside me, afraid and unable to express it. Expressing discontent in front of an important person feels like a small death.

I feel like this is one of the biggest personal challenges I will ever face, because this kind of dysfunctional way of dismissing my own needs, blaming others and bottling up anger is such an old part of me. I need help, and I would be more than grateful for your experiences and thoughts. Thank you in advance.