I totally agree with WePow.
Nobody is an island. Everybody is damaged, influenced, hurt by someone or in some way; your parents too. Just like everybody elkse they tried to cope, but unluckily for you not in a good way. Understanding that shows you that blaming yourself for their behaviour is useless. That is the first part.

Second part is realising how it affected you, and allow yourself to feel it, and stop denying the feeling. That feeling may be anger.

I remember once after a session I was extremely sad. I was very scared to allow that feeling and thougt, if I start crying, I will be crying for weeks. But I was so overwhelmed that I took a day off, just for crying. I only cried for about half an hour or so. And then it was over, like things had fallen into place, and I was very relieved. But I had to allow it first.