I hate my DSD

It could be worth talking to her school too about a counselling group for her age. I know my kids school has one for kids dealing with various issues (divorce/bereavement etc). She may need her feelings listened to and talked through

This child as much compassion as you think you yourself deserve.

Save yourself and your children OP, you can't change this.

She is already in a cycle of causing psychological harm to her.

This was an obviously traumatised 12 yr old, who has been massively let down by all those who ought to have her emotional needs at heart. None of them have stepped up, and OP blames this child for her own trauma.

Nobody is denying it isn’t very difficult, but OP (and more particularly her husband) are not going to come out of this smelling of roses.
Did they massively underestimate the level of damage the daughter has already been subjected to? Yes
Have they taken her seriously? No
Have they even tried to inspect what the daughter means by “I’m being neglected” - not going by these posts.

OP, the anger and distress this child is experiencing is absolutely normal for someone who has had to be removed from her mother. If she could articulate her emotions in a manner that was acceptable to you, what do you think she would say?

You have allocated yourself permission to show an ugly and compassionless side of your character with the expectation that the circumstances explain your feelings. Might it be possible that some of her ugly/ compassionless actions also warrant similar consideration?
When you think about the circumstances that led to her living with you being necessary, is it possible that she feels anger at her mother which she cannot express because she doesn’t want her to be besmirched in front of you.
Is it possible that she feels jealousy towards your children because they have the stable life she perhaps craved, and now she has to watch others get it up close whilst not being permitted to complain.
Is it possible that her normal teenage woes and hormones are viewed through the lens of her being a psychotic little cunt, rather than meriting “Wow, you seem angry- is everything OK?”
It isn’t clear but has anyone ever just listened to her, without commenting or trying to fix it, or making her feel like a burden.

Funnily enough I was reading about teenage brains only yesterday and the science demonstrates that only a tiny percentage of children are born “evil” to use everyday language, only a tiny percentage display psychopathic behaviour from birth despite growing up in a loving home.

The overwhelming majority of children are born normal and poor parenting fucks that up. So the theory everyone keeps spouting on here that op’s dsd was innately bad from birth is unlikely be true. It’s just much easier to blame a child for the dysfunction adults impose on them rather than acknowledge this fact.

I would step back for now. The 15 year old isn't your husband's am I right. Be careful in case he's treating her differently and she's upset/depressed over it and lashing out. You need to regroup yourself, one of you take the stress of daughter for a day or two (so she's in a better position to talk) and get to the bottom of this. Lots of listening. If she's consistently like this consider if she has someone in her ear backing her up on this too

You sound incredibly immature.

I hope you feel better.
You need to be able to vent, especially when she could potential ruin your life.
I wouldn't like to live with her either. 💐

So many people seem to want to excuse the unexcusable here. The OP isn't dealing with normal teenage antics by the sound of it. She's probably dealing with a narcissistic personality who will stop at nothing, including harming those around her to get what she wants.
We talk all the time about narcissists on mumsnet but they don't materialise out of thin air when they become mils. They develop that way as young people or may even be born that way, I don't know. But I do know they exist and they cause untold harm to those around them if given the opportunity.
It's too easy to blame bad parenting and sometimes that may be to blame. And environmental circumstances obviously contribute.
But some people are just bad ones and no amount of good parenting will alter that. You have my sympathy, OP. It sounds horrific.

Wow you hate a child, you need help

feel sorry for the kid

I really feel for this poor kid. And your other kids. Grown ups make choices for their own happiness and the kids get dragged along.

This girl has suffered, hugely. She has not been prioritised by anyone. You comparing with your own teenage years is, as you say, comparing 'apples with oranges'. Did your parents separate? Was your mum 'a nightmare'? Did you have to accommodate the arrival of two half siblings who got to live with their mum and dad, your dad, all the time while you only saw him from time to time?

This girl has suffered, OP. And she has had no choice about any of the things that have happened to her. She is hurt, angry and lashing out. The fact you have no empathy with this, and her parents take no responsibility for it, preferring instead to blame each other, is only exacerbating her feelings of abandonment.

No you're not obliged to care but don't expect a big pat on the back. This girl is being set up for a very unhappy life.

Then I would seriously be questioning the apparent support you are receiving.

And the fact you are still are using words like normal, narrasisst etc proves it.

No it isnt normal and any one who actually has a proper understanding of child development, impact of attachment along with the overlay of blended families would.

What she did isnt unforgivable. And I would seriously caution your mindset, because currently you still have small children who for the most part are still fully influenced and controlled by you.

In 10 years time that wont be the case. They will be primarily influenced by the peers. Which if they have a fairly stable and secure attachment type isnt to high risk.

How ever, throw in a few adverse situations and that can all change. Bullying, social media impact, poor self esteem. The list is fucking endless.

Then you could be facing a teen who hates the sight of you, experiments with drink or drugs, negative sexual experiences. And now the wheels have come all the way.

Zero control, poor emotional regulation, anger. And you could well end up sitting exactly were you are now.

Of course anger comes with dealing with teens with issues. But that anger becomes toxic and damaging to the child when it loses emotional maturity and regulation and compassion. With a dose of empathy.

Which you dont have.

Teens dont turn around and learn without a strong support base to do it. And plenty do. The world is full of perfectly functioning, happy, productive adults who went through hell as teens.

I think you should live separately from him and his child for your own mental health and that of your children's. They deserve a calm and happy home. I wouldn't see it as a break in the relationship, just as a break in living together, just until she's old enough to live alone, and then I'd live together again.

Therapists don't tell you your feelings are wrong. That is literally the point of a therapist, to listen to your feelings and help you manage them in a non-judgmental way.

This is absurd. The OP has my full sympathy, it sounds an awful situation but while a 15 year old should of course be aware of right/wrong and responsible for their own actions, lying to social services is not "pyschopathic". Teenagers have impulse control issues at the best of times. She may well not have given any thought to the consequences. Of course if she's done other stuff that is actually pyschopathic then she needs urgent help for everyone's sake, but we don't know if she has (or what she has).

Again OP, you have all my sympathy it sounds an awful situation but one I think you need to get yourself and your smaller kids out of as soon as possible.

I agree OP, making false allegations is not normal behaviour and beyond very young children is inexcusable. My youngest, age 7 or 8 at the time, once phoned Childline about some grievance, (bedroom tidying). Even at that age she was very sheepish afterwards and knew she was being unfair and shouldn't have done it. Her siblings, both around the same age also told her off. She didn't even lie as well, we did stop her watching TV and made her go to her room to tidy it.
My daughter is now a young adult and we laugh about it, I think she's still a little bit embarrassed though.
As difficult as they all were as teenagers, making false allegations about anyone, not just parents, it so far from normal I don't know why people are making excuses for her.

All the posters clutching their pearls at how mean they think you’re being 🙄

OP I feel the same way about my friends 14 year old. She’s a horrible girl. Yes she might improve with age (my DS was a horror from about 12 but he’s absolutely delightful as a young adult) but right now I loathe her. Shes nasty, spiteful, rude, ungrateful, aggressive and manipulative.

YANBU.

So she came to live with you at 12, 3 years ago? You have a 6 and 4 year old so you had a 3 and 1 year old? That’s going to be incredibly difficult age gap even in biological children.

It’s hard to understand the situation with so little info. I know you say you’re not looking for advice but surely you are if you keep posting.
Why did she move out of DM at 12? Does DM have new DP or children too? Does she still have contact with DM?

As others have said it can be possible to move out with your children and continue some relationship with DP whilst he focusses on DD.

But your language, vitriol and anger are yours to own and manage. If I was your therapist I’d be pushing you harder to not see your DP and yourself and children as the victims and your DD as some little monster. That isnt helpful or true.

Your DP decided to have 2 children with another woman when his DD was 8 years old and likely struggling back then. She had no say in the life you have all given her. Was her mother just as selfish? How will you feel when your DP decides to hear another child with another woman in 8 years time and it’s your children going off the rails? I’m not sure you’ll see him as the saint then.

Not always the case. One of my brothers was just plain nasty, sneaky nasty and cruel from the age of around 14. We'd all been brought up the same and the rest of us normal kids. My parents tried everything to help him out, he actually got even better treatment than the rest and it did nothing to help. Some kids are just little shits.

I’m very obviously not saying that, and you can tell by the way I didn’t use any of those words.

I made zero comment on whether children know right from wrong, and criminal culpability isn’t solely informed by knowing right from wrong.

There is literally no reasoning for the age of criminal responsibility being 10. Read up on it. It’s the lowest in Europe (now Scotland have increased it) and that’s not because of some special maturity children have in England Wales. As you point out, there’s no ‘magic switch’ at 18 so why would there be one at 10?

I understand how you feel, however, as a PP said, why are you in her life?
Get out, for yourself.

I had one of these, it was all her mother projecting on her & hormones. She had a lot of issues and she was a nightmare. We are now 6 years on and really close and she realised what a waste of space her mother was and what she was doing.

It does get better. It took a lot of support and encouragement for her to realise I was not the bad one and I was there for her. DH not a great help because he didn't acknowledge a lot of it at the time which we have reflected on.

As I said, we have a really good relationship now.

Honestly I feel for you. After the social services involvement that girl would have been out the door and back to her mums faster than she could blink. Dad could see her away from the house.
If he didn’t agree I’d have kicked him out as well.
Is sending her back to her mum not an option? You say she has no problems with her. So let her have her full time. Dad can visit if he wants to but she doesn’t come back to your home

I can tell that you’re at the end of your tether and completely fucked off and I would feel the same I think. Mind you, I couldn’t imagine living with someone who already has children because I just don’t think I’d be able to treat them as if they’re my own but that’s just me.
I don’t think she’s ’a poor girl’ but I do think that she’s possibly reacting to the shitty circumstances that she’s gone through. She’s been removed from her mum for whatever reason. She’s come to live with you and her dad and the two shiny new small children, plus shitty hormones at that age and it’s a recipe for disaster.
I don’t think you should divorce your husband but I do think it would be better if he moved out with his daughter. The current set up isn’t working for anyone. Good luck.