I couldn't quite tell but I think she is not living there now?  If that is the case, I'd let DH and SD do their thing.  I agree she is immature, insensitive and ungrateful to you.  I would disengage big time.  Really, what else can you do at this point.  I'd concentrate on my bios and your relationship with DH.  When he talks about her, go, "Hmmmm...what's on tv tonight?"

How old is she?

You know what - here is what I can tell you:

- you are now "Dad's Wife" to her and she wants to exclude you so she can have her dadee all to herself. She probably never liked you, you were useful to her and now that you are no longer useful you are disposable and she threw you away.

- As "Dads Wife" you can and should disengage completely from this person "Dads Spawn".

- Disengage from trying to participate in anything to do with her, if possible. You do nothing for her. No presents from you, no cards, no rides, no birthday money, no trying to connect in any way. You go full no contact with her.

- If he spends time with her it is NOT at the expense of you and your children. YOU are still the priority as "Dads Wife".

- when he spends time with her, it is somewhere else completely. NOT BM's house however.

- She is doing something called "Emotional Terrorism". Perhaps try to understand what is going on, so you can better prepare yourself emotionally. I had that going on with SD22. Now we are civil but it was always a battle with her (on everything actually) and shes always "your choosing your WIFE over your own CHILD". Fathers day I spent with my father and he took his two spawn SD22 and SD15 out to lunch. A very quick lunch, maybe 2 hours or less.

- If he is allowing her to be an emotional terrorist, then he doesnt need to really talk about her either - you as "Dads wife" are not interested. Thats how I am right now with SD22 Feral Forger and to a degree SD145 Backstabber/Munchkin.

Grieve the family you thought you would have, because you probably wont have it. Focus your energies and love on your bios. Hopefully she will grow up, but probs not.

I went through a lot of emotional turmoil regarding SDs and Thier emotional abuse of SO. But after a lot of reflection and counseling. I realized that this is the relationship SO chooses to have with SDs. He chooses to tolerate their behavior. He chooses to not set boundaries. 

I became SOs rescuer emotionally and in turn was causing myself undo emotional stress by becoming a part of their dysfunction. Especially since it was a situation in which I had no control.

I had to realize my role and step outside of it. I had to set limits with SO and SDs. I had to become emotionally uninvolved and direct SOs issues back on to SO when he brought them up . I made it his responsibility to handle his relationship with SDs and any issues related to them as well as the consequences of his decisions.

I would echo what others have said, but also would add the following from my own experience.  I entered a relationship with my DH, in 2002, full of hope that I would be able to form some sort of good enough relationship with my 2 SDs, who were then aged 5 and 7.  Due to severe PAS on BM's part, this didn't happen.  Younger SD would sabotage any outing I tried to take part in. After about a year of this I stopped going and disengaged to a large degree. It was the least worst soloution to an intractable problem, not ideal because I felt lonely and excluded every other weekend when they came. They were both nasty to me, right up until a few years ago when they seemed to mature a little bit and now they are at least civil to me. 

Since about 2014 they have not been coming EOW, instead DH sees them, usually individually for lunch or coffee, not at our home. We moved about an hour away from them a year ago, and I have made it clear I would like to be included in any future plans as they are now in their mid 20s - I have had enough of being sidelined. As you point out, it does make you feel that DH is colluding in this and doesn't do wonders for the self esteem. DHs often put up with shoddy behaviour from their offspring as they don't want to lose them, but it doesn't occur to them what it is doing to their partner.  

While it must be dissapointing to see your hopes of a "healthy" blended family die on the vine, It's also important to understand that everyone has their own sets of hopes and dreams about life and sometimes those views and preferences don't align.. especially in steplife.  I know it's also difficult to watch someone hurt your DH.. and I'm sure he was quite hurt that his daughter's time with him wasn't as successful as HE had hoped.  And it sounds like both HE and your SD said their share of hurtful things to each other.. and for that, he is feeling his own guilt there.. and that guilt is on top of the guilt he probably still carries from not keeping his "first family intact".  I don't mean that he wishes he HAD done that.. but that he recognizes that the adult choices he and his EX made did make life somewhat more complicated and difficult for his children over the years.

But, while I appreciate your optimism going into his daughter staying with you.. in reality, it was very likely that there were some real behavioral issues that were driving her late childhood change.  There must have been conflicts at Mom's and I'm sure that dad thought he could save his child from that.. when in reality.. his child was likely a full participant in the issues at that home.  And the issues sound like they followed her to your home.. a home with "dad's wife" and other kids and that was also going to be unsettling and an adjustment, to say the least.. and 3 months is nowhere near enough time for everyone to truly find their footing.

And yes, it's upsetting that she has now taken this stance of only wanting to see him without you... despite the fact that you feel you were the one who tried so hard to mend the fences to begin with.  And, I can also see some resentment towards your DH because he allows her this "boundary".  He should stand up for you too right? 

But, in the end, she is now an adult.. and as an adult, it really is her right to have relationships with people who she chooses.  She is also your DH's daughter and it shouldn't be a condition of having a relationship with him.. that you are included in their relationship and activities.. at least not all the time.  Now, that being said..it also means that if they are going to isolate their relationship as such.. that it needs to be well balanced with the other time spent with other family and friends.. so insisting on multiple outings a week to the exclusion of others? That isn't reasonable.  If he wants to have lunch with her a few times a month.. fine.  If he wants to have a call several times a week to "talk".. that should be ok too.. as long as the time isn't overwhelming everyone else's right to be included in his life.

And.. I don't think this is necessarily personal.  There could be many reasons for your exclusion.. and honestly, your DH should try to figure that out and if there are any misconceptions about you or your relationship or what happened with her stay with you... he should be able to address and defend you to her.. and let her know that he DOES love her.. but that you are his wife and he loves YOU also.. that his preference would be for everyone to be able to be civil together.. etc.. but if his daughter is not able to accept that dynamic now? it is really her decision.. and I do understand that based on his guilt to behaving badly when she was with you guys.. he is afraid that he will push her away again.

So, as long as he isn't totally wrapping himself up in "dating" his daughter.. I think that the best path forward is to allow him to spend time with her and not make it a her or me line in the sand.  He likely doesn't enjoy excluding you either.. but she IS his daughter and that fear factors in too.  He should also set some boundaries of his own... they can see each other on their own..but there should also be line in the sand things where he would expect you to be present as his wife.. and he needs to continue to drive that message home.  You are my daughter and I love you.. but SHE is my wife and I love her and she is my partner in life and while we may do our own thing and have our own relationships with people and do things without each other, on occasion.. she is still an important person in my life and there WILL be times when she is included and I expect civil behavior.  You don't have to love her.. think of her as a mother.. but you will respect her as my wife.

BTDT

The hardest thing ever is giving your heart, facilitating daddio and SD relationship, and then you are the one who is shunned.

Its really hard to digest. BTDT

The only way I got through this part was to busy myself and my thoughts towards the people that care in my life. She will be a headache heartache on so many "happy occassions" to come. Prepare yourself for this and invest nothing in her.

As for your DH he should respect and know that you are hurting from this. You are the one that facilitated this to begin with. DH should be kissing your feet for being such a good person.

IMHO the solution is zero tolerance, total confrontation, and delivering a state of abject misery to those deviating from acceptable standards of behavior and performance.  Minor Skids, Skidults, the toxic blended family opposition, ILs, etc... it makes no difference.

I expect my mate to have a spine, respect herself, and tolerate nothing less than she be treated with respect by her child, her family, and for damned sure anyone and everyone in the blended family opposition.  I have her back, she has mine.  I will not allow anyone to treat my bride with anything but basic respect and decency.  A standard that my dad set for how his wife is treated.  Mom has the same requirement for how her husband is treated.  That they have been married for 59 years .... has not changed that unequivocal requirement.

The thing that no one wants in our blended family adventure is for me to have to step in as the pain level will amplify to brutal, expensive, and eternal.  The shallow and polluted end of my SS's gene pool never gained clarity on this and pushed their pain level up, and up, and up over the 16+ years we lived under the CO by failing to recognize that they would not be tolerated to treat my wife disrespectfully or abuse my Skid.

Zero tolerance works.

You and your SO should try it.

No contact from the Skid, bring the pain on BM and the Skid until they respect DH's COd time with his kid(s).  Unacceptable behavior... bring the misery, etc, etc, etc.... They behave reasonably, they receive reasonable treatment from the quality half of the blended family equation.

Lather, rinse, repeat.