I find SD12 increasingly unpleasant

The reason sometimes is “I want…” . Some wants are reasonable,some aren’t. Sometimes it’s really not that deep.

That’s a whole load of drivel to justify poor behaviour. You don’t spend a lot of time around kids , do you?

There's also the possibility that she doesn't like you but hasn't yet developed the adult skills of tolerating you.

Unfortunately blended families never work completely. I don't much care for other people's children so it must be hard but you made this choice and she did not. All behaviour is communication (whether some people like to admit that or not) so maybe read some parenting books / child behaviour books to help you better understand her. She isn't being deliberately difficult, any more than an adult who is struggling would be so the onus really is on you to be kind here.

Children have to be selfish. They are dependent for survival on other people. Selflessness is not an option open to them in childhood, but being trained towards it helps them achieve adulthood. Likewise, manipulative is what people with no power have to do to survive - again, a healthy adult should not have to be that, but a child may.

Not without reason. Behaviour is a communication

Because no child ever has been selfish or manipulative?

while you have always gotten on least with her she’s at a tough age, I always remember how up and down ds was at that age with hormones. I think definitely bear that in mind and try your best to be there for her, kids need adults to be present and parent them

The two states are not mutually exclusive.

I'm amazed by all the posters who were never an obnoxious teenage (or just pre-teenage) girl.

She isn’t a selfish manipulator she is a child

Yeah, she's not so much the issue as your DH is!

She's a child, likely in/on the cusp of puberty, who has to share attention of both parents, with not only 2 siblings but also a step parent.

All behaviour is communication and sounds like she acts up due to lack of positive attention? What one to one time does she have with her dad?

He needs to step up, and spend quality time with each of his kids as well as setting boundaries around appropriate behaviours e.g stop talking, or leave, ignore her ignoring him, and call her out on her rudeness re: "I'd rather have the cash". Equally, on that last point, YOU can easily say something light but to the point in response to that - along the lines of "good to know, but thats not on offer".

I remember how hard managing my emotions was for me as a teenager, so when mine are utterly vile as they all are at times, I try to remember this!

They may physically be older, but developmentally their brains are still developing as rapidly as they were when they were toddlers! Tween/Teenagers can be equally as irrational and emotional as toddlers, but it takes us by surprise by they have better vocabulary now so we expect more rational behaviour.

I really feel for you OP. Step parenting is the hardest thing I’ve EVER done. I’m sorry you’ve been slammed by so many who clearly don’t have the same experience. It feels like trying as best possible to bond but at the same time maintaining your own boundaries would be a good option. It’s hard and I wish you all the best in this.

Yes, try to build a bond in some way. And the fact that she is 12 means she'll be becoming more independent in a few years anyway, building friendships of her own etc.....especially if she is outgoing. So her focus will shift towards others too as well as the family members. Maybe encourage hobbies she really enjoys.

Women cheat too, you can eyeroll as much as you like.

Glad it wasn't just me that immedietely had an eye roll at that. Every single stepmother thread on here has the same backstory. The ex wife always ended up cheating and leaving the poor husband for the other man. Exactly how many women are there out there are finding the time to have affairs whilst pregnant or with young children? Not many I would wager.

Whether she discussed it with the parents or not, it’s certainly not the OP’s responsibility to decide to have her stepdaughter assessed. She has two fully functioning parents (well, that’s maybe a bit of a stretch) who should be capable of making that decision. It seems that you are able to diagnose her via the internet, so maybe any possible ADHD traits have already been identified and discussed by the people who know her in real life.

Would it be possible for you not to live with thier dad?It all sounds incredibly hard work and personaly I would be asking myself do I want this for the next 10 years until they are off doijg their own thing.

Nomas, you are entitled to your view, and I have mine.

The OP has some excellent support on this thread and I hope it will help her with her predicament as she seems keen on resolving the problems in her blended family set up.

It sounds like the girl is just a normal albeit perhaps spirited 12 year old and with love, guidance and support she'll grow up to be an amazing young adult no doubt. And OP should be very proud of herself for caring for other people's offspring despite struggling with the set up.

I'm sorry to hear that you had a hard time with your sister, thats a shame.

Her siblings will get well & truly pissed off with her the older they get, and that will probably rebound on their father. Hope he's prepared for that.

she sounds like a kid behaving like some kids do, she’s not high on crack or setting fire to the sofa, I'm sure theres a lot you can do to create a more positive, warm, nurturing environment. She sounds like an unhappy or insecure child who needs more regular 1:1 quality time with her dad and also some quality 1:1 time with yourself. You could opt to build the relationship with a little thought, like an adult.

Nope. Strong, independent women are not raised as selfish manipulators. They are raised to see fairness, equality and knowing everyone has their worth.

I fully support raising daughters that do not put up with being treated like a doormat. However, daughters that treat the rest of their family like a doormat need reining in.

What a weird response. OP likely has talked to her husband about this previously and he’s passed on there views to OP. Why would you assume she talked to the school? I doubt OP attends parents evenings

Cannot understand why on here, everything is always someones fault.

Things can absolutely just happen, and sometimes it goes shit, with all the good will in the world.

Sounds like op has tried a lot. Maybe a few lessons on how we can't just have a tantrum when we don't get whatever we want. It's a good lesson to learn. She's old enough to know this now. Especially as her siblings are changing what they want to do to avoid a tantrum - that's manipulating other people to get her own outcome. Completely unreasonable.

She absolutely cannot rule the roost. Sending hugs, op x

I'm sorry, OP, I should know better than to make assumptions 🤦‍♀️
So SCs mum left their dad, that does make a difference. But could still be easier to blame him than her mum, depending on what kind of relationship SD12 has with her mum.

Your DH definitely needs to try harder to get the discipline right. It's not fair or healthy to the others to have SD12 ruling the roost all the time. Eventually resentment will build, and a whole new set of problems will develop.

It really needs sorting before the avalanche of hormones hits...