Yes, I have been wrong about that. I really did think I'd read that he told OP he loved her daughter as his own but it looks like I added that but myself. OP's posts very much gave the impression that she thought that too!
See, this was my inkling all along. I posted this pages ago. OP has heard what she wanted to hear, because she wants this to be the "instant" family she hasn't got for elder DD. As PP said, she must have really thought her ship came in.
Eg the DH says "I will raise her with you"
And OP deliberately hears "I will raise her with you as my own".
Like you, OP added that bit on the end. And you only did that because of the way OP tells the story insinuating it. OP now is up in arms that what she wanted to hear isn't what is happening. She's got fantasies in her head of this brilliant supportive wealthy family who will scoop up her eldest and lavish all this support etc on her, despite the reality being that from day one, she wasn't in wills, or thought of as a granddaughter. OP did know that. She just pushed on with the fantasy version, because she thinks it's somehow going to materialise if she keeps acting like it will.
I think OP would have been trying to seek validation of this, "oh it's wonderful how you raise her as your own, DH" to almost plant the seed/get him to say those words. Because she wanted to create that situation for her eldest. That thing where if you say something often enough, and loud enough, it must be true, right? She knew it wasn't the case. She was hoping she could change that.
Whether he used those actual words or not - he has acted in a way that made OP think he saw the two girls as equal - and now he's making it crystal clear that he doesn't.
I don't think he did at all. I think OP has deliberately interpreted someone saying "as her own father won't even turn up, now we're married I will do the day to day providing and parenting with you" as "this is now my child, as my own, and my extended family will now become a surrogate paternal family".
Right from the start, the DHs response to OP raging at him was "it's not my fault her dad didn't step up". And this makes so much sense. The DH is willing to step up, and do the groundwork each day. The boring but absolutely essential daily life stuff that every child needs. Food, clothes, housing, holidays, birthdays, social stuff. He is doing all of that, and OP glosses over that this is all voluntary and a thousand times more than actual dad. She literally just ignores everything he does every day. The real parenting. The only person (other than OP) who's ever been interested in this child, she's threatening to divorce because she didn't get a wedding invite just like the other 6 "step nieces/nephews".
She's been given the keys to the candy store, she expect the deeds to the shop.