Hey OP, I’ve read through you thread and posted on it at the start.
Firstly you’ve been an absolute saint, and as a step parent myself I know how hard it is to balance and be fair with things when everything is going well. Quiet how you have managed to remain so measured and despite everything still caring about your SD shows what a truly genuine thoughtful and caring person you are.
I suspect you already know the following but I don’t think it’s any coincidence that every time SD or her mother don’t get what they want the ante is upped and the stakes are raised. First SD needs to come because she’s not coping at home, than it’s because mum apparently is dying of breast cancer, then SD is suicidal. It’s only going to be a matter of time before they are going to say something that your DH can’t ignore and forces him to over rule anything you’ve previously agreed. Have you noticed that all the reasons are the sort of reasons you can’t question or argue with? I m mean who argues with someone who is dying of cancer? Who argues or denies a child who is suicidal?? You don’t, you can’t....well technically you could but you’d look like an awful human being doing it!
I may have this wrong but it seems to me that the ex/mother is the emotionally abusive/emotionally manipulative one. I think poor SD follows her lead, and models that behaviour because that’s what’s she has learned from her mum. It seems that they both pull out all the stops and are unscrupulous in continuing until the behaviour serves it’s purpose and gets them what they want....until the next time, and there is always I next time. I hate saying this about people I don’t know, and indeed about a child, but reading your posts this is the most likely assumption I come to.
As for your DH, he isn’t stupid, he is absolutely wise to both their behaviour. The crutch here though is that this behaviour serves a purpose for him too, its getting him well on the way to what he wants, which is his daughter back at home with him, and with you. He knows the tricks and the BS, and I’m sure that deep down somewhere he carries an immense amount of guilt that he broke up his child’s family by leaving, guilt that his child struggles so much and probably a deep shame at how his child behaves. He knows he is in part responsible for all of this, but I think perhaps to actually admit his daughters faults feels like a betrayal to his daughter and he can’t bear to be seen to be doing this or feeling like he is hurting her more than he feels he already has. Of course SD and mum both know this and use it and play it to their advantage, by confirming his worst fears and calling him out on his leaving, his parenting, his priorities. All the while even though he may know that they say these things not because it’s necessarily true, but because it works as a stick to beat him with and guilts him sufficiently to bend him to their will. I suspect he knows this, yet can’t acknowledge it because acknowledging it means admitting blame, taking responsibility and feeling the hurt rather than brushing it under the carpet. Not only is this painful, and I’m sure it’s a wound that runs deep, but if he admits it to himself and to you he knows this would mean changing his behaviour and how he deals with things in the future.
I think the reason why DH won’t acknowledge or admit the above and change the way he deal with things is two fold. Firstly because perhaps he can’t see any other way to deal with it than he already does. He is deep in the FOG (fear/obligation/guilt) and seeing a better path to move forward is obscured from view. Secondly because the guilt he has regarding his daughter means that all he wants to do is indulge her, to please her, to make her feel his love in whatever way he can. He thinks or feels that giving his daughter boundaries and rules (which she clearly so desperately needed in the past and needs now) will be perceived as some sort of rejection. He worries that she will feel he doesn’t want her, and also worries that she won’t want him.
All of the above is not something you can tackle OP, I appreciate that you love your DH and that you want what’s best for him and also SD but this is not something that you can sort with love, support, understanding and caring alone. They can all have all the understanding and caring in the world but these issues are so multi faceted and involves so many people and have gone on for so long that coming to any sort of lasting peaceful resolution is almost impossible. The only hope of doing this I think would be for ex, SD and your DH to have family therapy, and that involves everyone cooperating and everyone will to acknowledge things, committing to move on from hurt and be willing to change for the future. I don’t get the impression from what you have said that this is likely to ever happen.
I think you know that at some point in the future whether you agree to it or not your SD is coming back. The only obstacle and objector here is you, it’s 3 against 1 and whilst your objections are being heard at the moment, I don’t hold much hope for this lasting very long. In fact I suspect that once your baby is here, not long after your SD will be too. They will wait until your too tired, to hormonal and too busy with the baby to put up much of a fight. I think you need to plan for this, and I think you need to come to the harsh realisation that your DH is not on your side, he is on his own side and ultimately will go against you and against what you want and what you need. He/they will do this to you, he will think that you won’t make him and SD leave once you’ve had the baby, he will emotionally blackmail you too, telling you how unfair it is that he’s welcoming a new baby home whilst his firstborn is left out in the cold, and how can he possibly live with that. You’ll be so emotionally battered and scarred that you will feel you have to give in, and that’s politely assuming you get a choice in that matter and that SD isn’t just unexpectedly left on your doorstep.
While you still can I would be making a plan b, and I would be working out what you want to do if and when this situation arises. At the end of the day as bad and as sorry as you feel for SD she has a mother and she has a father and she is their responsibility. Your kids have you, they are your responsibility and they deserve to have someone put them first too, just like DH wants to put his daughter first. It’s not your children’s fault that your poor SD is in this position, they should not have to pay the price of the mistakes others have made. They deserve to have the best mother they can, and that includes having a mother who is not stressed and fearful of being in her own home, worrying about allegations that could cost her her job or worse. It’s not just that you don’t deserve it, your children don’t deserve it either and neither one of you created or are responsible for this situation, so why should you be? You need to protect yourself and you need to protect your children and sadly I think that in order to let your DH do what he feels he needs to for his daughter it needs to be at the expense of your marriage. If this doesn’t cost you your marriage, next week, next month or even next year, I think ultimately it will cost you your marriage at some point in the future, it’s just a case of how long do you want to let it go on for? Sorry to be so doom and gloom about it, but I think you are trying to rescue and repair something that you just simply can’t and even with all the will and love in the world I can’t see this lasting without you either splitting or you and your children being walked all over time and time again.
I’m sorry this post has been so long, and I’m sorry if it’s upsetting. I really do hope that you manage to find some peace and some calm and I wish you all the very best for the birth of your lovely new baby. 