No one needs to justify their existence. Existence is valuable in and of itself, not derived from what you can do or be or experience.
"In the same way that your heart feels and your mind thinks, you, mortal beings, are the instrument by which the universe cares. If you choose to care, then the universe cares. If you don’t, it doesn't."
I think you are misapplying the principle of "words are how you use them" here; "his husband" is used not-infrequently and is grammatically valid to any English speaker. There is nothing to correct in the original text.
What this is using, however, is statistical frequency of use, which is a different thing altogether. And you know what relies on statistical frequency of language like this? LLMs.
English is full of words and phrases that have secondary meanings, and even obscure or contextual meanings that are real and correct! We cannot cede less popular language choices to AI spellcheck or we lose our own voices and experiences. Acknowledging that gay people exist is a tiny microcosm of this, but it's important in many other ways too.