So - IMO, this is one of the traps that people fall in when they become a stepparent: the idea that the kids will love and accept them as another parent.

In this case - she doesn't. She doesn't see you as a "stepmother", she sees you as "Dad's wife" (which by the way, is also how my SS19 sees me, though he's not rude to me in any way.  I also see him as "my husband's son", so it works out well). 

As a stepparent, you can't make the skids love you or see you as a parent figure. On the flip side, though, you don't HAVE to act as a mother figure either - which means no more baby clothes, no more money, no more showers, no more making her write thank you notes, etc.   She doesn't want or need another parent, so stop trying to be one, or expecting her to see you as one.

As for the baby, you can still be part of it's life even if you aren't "grandma".  You have your own kids to be "grandma" with.

his 2nd wife. His youngest son referred to his sister as “same dad different mum” when asked by a friend who that kid was... he just had to emphasize that they have different mums and not acknowledge her as just his sister. That person looked at him weird like wtf..

so its quite simple for me with my skids, you don’t get to emphasise to your dad that he has a new family and you don’t want to cause problems or issues when you actively tell him to dispose of assets of his to your mum and you 3 and exclude me and my 2 kids with your dad then in front of family try to play siblings of the year. You also don’t get to benefit from trips to my country every year or have the privilege of living in a home i am purchasing with your dad (aka my husband), you get to be the strangers you are... 

its not worth trying to fight to be their friend or supportive. If they’re horrible to begin with, there isn’t much you can do to encourage a relationship or make them appreciate all you do because they’ve had everything handed on a silver platter. 

Kids who get everything handed to them withiut having to earn things do not appreciate ever!!

She doesn’t want you to do these things for her. Stop doing them. It will take time but maybe over the years you will get to know each other and develop a good relationship. It hurts when people don’t like us when we want them to, but that is life sometimes and chasing a relationship with those people is pointless. 

Listen to her words, she doesn’t see you as a step mother, you have not raised her. She sees you as her dad’s wife. She wants to have an adult-adult relationship with you and not and parent-child relationship. That adult relationship may take time to develop, it may never develop  . You are just going to have to find a way to live with this.  

The only thing you have done wrong is in persisting on trying when it was clear she was not interested. You are clearly generous and thoughtful, but this is a new situation for you all and navigating it may be tricky. 

My SD's don't see me as an SM nor do they want me as dad's wife. I've learned to stay away. We think our generous natures will get them to like us but they just see us as being in the way.....of what I don't know. I haven't seen my OSD in over 4 years and it's been glorious. Cut yourself off from your SD. If she wants you in her life she can let you know.

You sound like a generous person. What looks to be the problem is expectations. She certainly does sound like she's jaded, and I think it's actually okay for her not to fully embrace you after being in her life for barely 3 years. Are you your husband's second wife as well? Has she had a previous step-mother to cause her to be jaded? Also, what are your expectations exactly? Aside from more gratitude, are you wanting to be closer to her emotionally the way she is with her dad?

I'm actually in a similar situation, except with my own step mother. My dad married her when I was 22 (13 years ago), immediately after my first step mom who was traumatically abusive. He is the desperate type who just cannot be alone, hopping from one relationship to the next. Luckily his wife now is nowhere near abusive, she's a hard-working, pleasant person. (since reading your post, I'm catching that I call her "his wife" and not "my step-mom."  I'm just not close to her, and I don't really want to be. I always buy her gifts and am very kind to her when I see her at holidays. I am definitely jaded and protect myself even though it mostly has to do with my dad's issues.... long story. Anyway. I like having my relationship with my dad separately, and that's okay. 

Ultimately your SD is allowed to have her own relationship with her dad, and I think it should be encouraged. It's also natural she would be closer to him than to you. It seems a little extreme to go from showering her with all kinds of gifts and when she doesn't meet your expectations, doing a 180 and not wanting to be in her life at all. Have you talked to her? What about having a relationship with her based on reaching out to see if you can provide emotional support rather than getting her things? That's what I think would be best. She could show more appreciation, maybe that will come with time and maturity. But maybe she needs a more intentional, emotionally supportive connection with you. 

My advice is to be there for her with her baby because there's a chance you could regret it. You don't have to get her anything anymore, you've done enough spending. Being there at the hospital would be supportive to your DH, and to the potential to reconcile the relationship with SD. 

So, is the real issue how she treats you, or how she introduces you? Because how she treats you is rude. Telling everybody except you that she was pregnant, inviting only her dad to dinner to tell him the news, was rude. She may not consider you any kind of mother but you are her dad's wife and should be respected as such.

Definitely stop doing things for her, as she doesn't appreciate any of it. That is the problem. Frankly, if she couldn't even bring herself to include you in the announcement of the baby, I would not have given her a baby shower. You do not have to be a doormat.

I don't care how my SD introduces me (or thinks of me), but she does respect the fact that I am her dad's wife, we are a couple, and she would never act like I don't exist.

My SD has introduced me as her step mother, and frankly, I think it was uncomfortable for her and I've been in her life for 23 years, since she was 5. We have always had a decent relationship and that is what matters. Referring to me as Dad's Wife might mean something negative to others but it doesn't tell them what our relationship really is. They just think it does. Now, if she introduces me as her Step Monster, that might be a different story.

She has a mother, so I did not "step" in and be a mother to her. I am not offended if she doesn't call me her step mom.

How do you get over it? You just accept that she doesn't want you as a primary (or even secondary) role in her life and concentrate on your husband and YOUR kids. Let your husband do whatever for his daughter and you can sit back and focus on your life. That also means that if he decides to babysit, that is ALL on him.

I would gather that you are generous with your bios and want to be generous and giving to SD. Is her mother strong in her life? Or are you and DH pretty much it?

I would suggest that you disengage from SD20. Do not go over the top in anything. And certainly no more parties that no one shows up for! Im not sure if thats because she doesnt bother to invite anyone or that she doesnt have any friends, but seriously, shes being ungrateful, not jaded. Shes definitely taken you for a financial and emotional ride thus far! You are still new to this (heck im new too, at 5.5 years in) and you are still in that eager to please mode.

STOP! STOP THAT RIGHT NOW.

Focus your energies on your bios and the SDs that are actually grateful for what you do. Value yourself and what you have to give.

Be there for DH as gramps, and thats it. Be happy she has shown her true colors pretty much all along.

Wife trumps the SM title.  DH needs to understand that his toxic spawn has earned a write off and no marital resources will go for her support or the support of her OOWL spawn.

Daddy needs clarity.  The SD does not mater.

IMHO of course.

I have two SD's, to YSD I'm most definately SM, to OSD even saying "my Dad's wife" is difficult (if she could say some nasty swear words in place of Dad's wife beleive me she would prefer that, she behaves as if any mention of me in a sentence involving anything to do with her including her Dad is repulsive)....and like you, this comes after years of going out of my way to do so much for her, all in an effort to let her know how much she meant to me and how I considered her my family

Yes it hurts and yes it's so common with step-parents

I've found that once I finally accepted that my OSD will never accept me as anything more than a hated, unwanted person in her father's life and that she will always not even be able to tolerate my presence in any event or moment in her life, and nothing I do will in any way ever make her change, like or accept me, or show even an ounce of apprecation for my many sacrifices and kindnesses, then I finally stopped all and without guilt

She introduces us as "This is my Dad (DH's name)" and then after an uncomforable pause "and his wife" - OSD makes a point of emphasizing it most especially to me. 

And yes Tog is right, it works two ways. 

My OSD has now simply become "my husband's daughter"

I'm polite, respectful and upbeat any time I'm forced to be around her (although we're 'cut off' right now) but to me she is simply just DH's daughter, not family to me nor anyone I treat as such any longer

If you're looking for advice; let your SD dictate the relationship. If you are nothing more to her than Dad's wife, then sure, be that and nothing more. Let Dad look after all her many demands and if he can't oh well, someone in her family will. 

Set an example for her of what a decent, mature, well-grounded person is like and treat her with common human deceny - but that does not mean she is family to you or you need to be even remotely parent-like to her in any way

And for what it matters, my YSD does call me her stepmom and she is much more respectful and 'loving'....but I've long suspected in her case it's simply an act to win favour with DH, and is even more so when she wants something from me. And to be honest, that is even more hurtful when you suspect that someone is a big phony with you about something you would never be anything but sincere about

So in a way, perhaps it's a good thing your SD is showing you who she really is, where you truly stand, and therefore you can choose how to respond to that going forward!

Wishing you all the best with it!!