How would you interpret this phrase?
How would you interpret this phrase ‘It was what I had wanted to do’?
Is it an emphatic structure in grammar?
I know the typical emphatic structure is ‘it be…who/that…’ But I’m not sure about that phrase.
Thanks. It’s from A Farewell to Arms by Ernest Hemingway.

the context:
That night at the mess I sat next to the priest and he was disappointed and suddenly hurt that I had not gone to the Abruzzi. He had written to his father that I was coming and they had made preparations. I myself felt as badly as he did and could not understand why I had not gone. It was what I had wanted to do and I tried to explain how one thing had led to another and finally he saw it and understood that I had really wanted to go and it was almost all right. I had drunk much wine and afterward coffee and Strega and I explained, winefully, how we did not do the things we wanted to do; we never did such things.

Question

How would you interpret this phrase?
How would you interpret this phrase ‘It was what I had wanted to do’?
Is it an emphatic structure in grammar?
I know the typical emphatic structure is ‘it be…who/that…’ But I’m not sure about that phrase.
Thanks. It’s from A Farewell to Arms by Ernest Hemingway.

the context:
That night at the mess I sat next to the priest and he was disappointed and suddenly hurt that I had not gone to the Abruzzi. He had written to his father that I was coming and they had made preparations. I myself felt as badly as he did and could not understand why I had not gone. It was what I had wanted to do and I tried to explain how one thing had led to another and finally he saw it and understood that I had really wanted to go and it was almost all right. I had drunk much wine and afterward coffee and Strega and I explained, winefully, how we did not do the things we wanted to do; we never did such things.

Answer

'It was what I had wanted to do’

"What I had wanted to do" is a noun phrase which can be used like a noun.

It is a different in structure and usage than the "emphatic structure" you mention.

1. It was for that reason that I came. ("emphatic".  "It" = "that...")
2. It was what I wanted to do.  ("It" refers to something real)

In #1, "It" doesn't refer to anything other than "that I came".
It can be rewritten as "I came for that reason", in which "it" disappears.

In #2, "It" refers to something concrete independent of "what I wanted to do".
It can be rewritten as "It was the thing that I wanted to do".
"what" plays the role of "the thing that..", a noun(thing) and a relative pronoun(that).

Here's a similar example:
"Who you are is simply determined by who or what you follow."

"Who your are", "who you follow" and "what you follow" are all independent noun phrases.

Answer

Yes, he is emphasizing that he had really wanted to go, but things happened and he did not make it.