AIBU to worry about my stepson's aggression towards the younger children?

If your husband refuses to do anything about it you need to take him to therapy as his own issues are getting in the way of effective parenting

He doesn’t seem to have stability, might be more aware of other family units and is showing this with lashing out, he needs care and support.

I think you all need help. This isn’t just a child problem. He shouldn’t just be spent to therapy. With young children, the adults around them also need to be heavily involved in the therapeutic work/intervention. From his world, he doesn’t have much stability- it’s quite messy for him.

Please tell us he’s taken his son to Disneyland Paris too…

If your DD tells school about the abuse she is receiving at home your and you partner will have an awful lot of explaining to do. His overt misogynistic violence will not be tolerated over your younger children's welfare. They will be removed from your care if you cannot provide a safe home for them. Social services can and will leave you both with the violent teenager and remove the younger children.

While your stepson has never lived in a nuclear family unit, he may now be more aware of what it means to him - he’s a bit of a floater between 2 very different houses.

that cannot be easy, and as a child he is acting out with poor behaviour because kids often cannot make sense of their world or emotions.

This isn’t your responsibility, but I think he needs therapy and as a parent I would be trying to get support to help in.

for you, I’d never leave my kids around him unsupervised.

The poor SS is having a horrible time between his parents but you are doing nothing wrong and are doing the right thing protecting your daughter

i was older, about 10 when we nearly became a blended family. My brothers and I used to fight but it was nothing like the pain I got from my could be step brother

you shouldn’t have to take your children out of their safe environment to accommodate him

Your husband really should not have produced another child when he can’t look after the son he already has… but that’s too late now isn’t it !

I would bet your step son’s problems are a product of his environment, rather than any neurodiversity.

Poor boy probably confused as hell by all these step relatives and half sister and god knows who else in his life !
sounds like he is crying out for some stability .

Initially I'd make a real point of taking all the other kids out and leaving dh and his son to it. Every single time, without fail. Seperate spaces entirely at home. Even of that means dh and dc share a room and you share woth the other kids.

Force DH to live with his choice until he can address it.

Your DH needs to parent him everytime, not just when other adults witness the violence.

Your SS needs counselling, no ifs and buts from your DH.

If your DH doesn't engage with correcting his behaviour and helping his son. Then you'll have to do whatever necessary to protect your little DD. Visits at grandparents only, or living apart but together just to throw out a couple of options.

Edit to add: These things take time so in the short term, SS is never left alone with DD. Your DH has to supervise him 24/7. That'll be enough motivation to sort the root of the problem.

(From a fellow stepmum who is dealing with similar issues)

@Wafflecakes also, I know there’s lots of people saying blended family’s never work, but they can. It’s more hard work for sure especially when the kids are teens and there’s gonna be rough patches - but my parents both remarried and had blended families and it worked out. I know a few blended families now as an adult and I will say they range in how successful they are, but it can work. You’ve got your work cut out I won’t lie, but if you all put your heads together and communicate I’m sure it will be fine. I look back on my childhood and it was happy one, I am now and adult and love my step mum and step dad and I appreciate them and all they did for me and my siblings and I’m glad both my parents found happiness. Yes, the majority of blended families have their issues but if you work on it it can work. :)

Your partner is a shit dad to all his kids.
He doesn't get a medal for bringing his child to football and booking a trip to Portugal with his son, while you are left at home with all the other kids.
He's having a great time for himself isn't he

Your SS is being failed by both his parents. Your DH for not dealing with his son's aggression with consequences, and his DM for her gentle parenting approach. He is also learning aggressive behaviour from playing violent video games and could be experiencing it in other areas - school, football, friendship groups, TikTok etc. You can't do much about his mum, but your DH needs to step up and his son needs to see a counsellor. If he refuses, and continues to put his DD at risk from his son, then it's up to you to take action by separating from him. Be forthright with him that that may be the consequence if he keeps burying his head in the sand.

My son is a similar age and the aggression he comes across at football, both playing and watching games, can be considerable.

If their dad/son bond is quite football heavy, it may be that this is how he thinks his dad wants him to act. No consequences would back this up.

I think his mum and dad need to sort him out and you need to protect your own children. He needs to see a counsellor, and his dad need to get his head out his ass in regards to his son showing obvious signs of distress. It’s alright now while he’s young and it’s easier to manage him physically, but boys grow and they grow fast. Tell his dad he needs to collaborate with his ex, get his son the help he needs or you and your kids are moving out.

Interesting that he targets the girls. You need to do a bit of detective work about what sort of environment he has around him at his mother's - or rather your partner needs to sort this out.

It sounds as though he's absorbing some nasty misogyny from somewhere.

Your children don’t have to be inherently annoying to be annoying to him!

Sounds like it might be an idea for the eow that you kids spend with their dad to the the weekend your DSS spends with you though. That should lessen the impact on everyone.

You may well have thought of that already but it’s not clear.

There could also be trauma going on somewhere else altogether like at school but your DH does need to get his act together and start trying to get to the bottom of things. Ultimately it’s on him to do it!

What would you like to see happen here OP? What do you think will help?