I dont want to think that he has had a trauma, and therefore it isnt his fault, as that just makes me feel sorry for him and makes me feel guilty that I wasn't understanding enough, and didn't meet his needs enough, and that it is my fault and that he is just a lost little boy who needs love and nurturing, and why didnt I give him that?
This right here is your problem. Where are you in this? Where are your needs, where is your right to love and nurturing? Absolutely nowhere. It's as if you don't even exist as a person in your own right, with needs and feelings in your own right, but just as someone there to support someone else.
This is all being projected onto him at the moment but it's something you learned in childhood, for sure. This is a result of how your parents treated you. You were there for them, they weren't there for you - a complete reversal of how it should have been. This is your trauma and it's your job to fix what went wrong for you, not what went wrong for him.
It's very possible that needs of his went unmet when he was a child. But it's his responsibility to deal with that, not yours, can you see that as a fact? And nothing he went through gives him carte blanche to treat you like shit, as he has done. Nothing he went through should deprive you of your personhood, but that is exactly what has happened here. He couldn't even get your name right, FFS, how much more stripping away of your personhood could you take?!
I'm really glad you're looking into counselling. You really do have some serious stuff to unravel from your own childhood, and it really helps to have some good support. None of this is your fault, but it is quite alarming the extent to which you are willing to abnegate yourself in favour of "rescuing" someone else. Might be worth reading up on co-dependency too.
Sorry if any of this comes across as harsh in tone, it's absolutely not meant that way. I'll say again: none of this is your fault. You took a really courageous step in starting this thread, and taking a stand on your name, this has all been very painful for you, I know. But I really think the issues go back to your childhood and unless you deal with that, instead of focusing so much on him, you run the risk of repeating the same pattern over again.