To think DP’s gone too far re room situation?

I don't dispute that the 19-year-old is obviously having a tough time, but I wouldn't have him living with me or kids of mine if he'd behaved like this.
I think his father needs to sort out somewhere to live for him. Houseshare maybe with known and trusted friends, or DP can move in with his son, or find him a place of his own and check in on him regularly.

Your SS clearly needs help and his dad needs to step up and support/parent him. How about your partner rents a 1 bed flat for him and SS. SS gets the living room. Partner puts time into getting SS into work, away from all day gaming and weed. Once SS is stable partner can move back in with you, leaving SS in the flat. I wouldn't want him in the house with my children but you could meet up for a family meal every week maybe?

You’ve got a 4 bedroom house and 4 kids. Everyone needs to be made to feel welcome and equal. What happened before is irrelevant as now the circumstances have changed.

If you value your partner you need to move into the living room and let his son have a bedroom.

if you don’t value your partner he and his son need to find somewhere else to live.

Come to think of it, even if I had the space, spare bedroom etc, I STILL wouldn't be letting him stay.
He is a danger to your younger kids, not earning and feckless. If DP didn't like that, he could move out, too.
I feel outraged on your behalf, OP.

Your DSS has been accused of sexual assault and your DP thinks it's okay for him to move in? HIs own mother has kicked him out for this reason but it's okay for him to move into your house?

Bat and shit come to mind

Where Is SS sleeping and gaming now in your house? Key question really.

This. I suspect he left his ex to do all the parenting of his eldest son, you've obviously done the vast majority for your joint kids given he didn't live with you until recently, and now he's expecting you to house his eldest and get him back on the straight and narrow. He's a lazy feckless dad, and you and all three of your kids will be better off if he and his eldest go to live elsewhere.

The “he’s an adult” applies just as must to the 19 year old as the 18 year old, and I can’t believe he’s suggested moving your son in the middle of his exams! The fact that it is your house means that you get the deciding say here. To be honest I would not be welcoming a 19 year old NEET with drug issues and a history of theft, violence, verbal abuse and possible SA into my house with an 8 and 9 year old. And now you know how your “D”P really feels about your son and about his rights over your house I wouldn’t be welcoming him back either.

The 19yo shouldn't be moving in at all. He should be finding his own place to live. He gets a job and pays for it. Or dad pays for it (or they move there together). He wouldn't be moving in to my house with my kids.

He doesn't sound like a safe person to have in the house with your younger kids.

I typed my reply before seeing your update. I couldn’t have someone accused of sexual assault around my young children, no way. He wants to prioritise his son, fine he can do that somewhere else!

Are there any other rooms in your house 5at could become a bedroom for DSS? How long term do you think this situation will be? If your older DS is doing exams does that mean he will be going onto university in the autumn?

If no agreement can be reached then DP needs to move into his own place to accommodate his son.

DP keeps saying “he’s just been through a lot, he needs time”

He's caused troubled and is now left with the consequences of his very own actions - had he behaved himself in the first place he wouldn't be "going through a lot" He needs to take responsibly for his behaviour and not be walking into someone else's house and moving their son out of their bedroom so he can have it as a fucking prize

Why are you allowing this violent useless grown adult into YOUR home with young children, seriously whats more important to you your children or your partner, also why are you allowing your partner dictate to you who lives in YOUR home,.seriously!

Is there a reception room that could be a bedroom for now?

If you have a spare room ie living or dining or office space he could use then I would have a strict contract/rules for him to agree to before allowing him to move in there. If not then dad needs to step up and help dss organise a place/room etc while teaching his son to be responsible work pay bills etc etc

And yes, this. With bells on.

Given the reasons his mum kicked him out, I wouldn't take him in. You have your young kids to think about; they come first for you. He'd be a negative influence on them, and he sounds pretty volatile.
Help him find alternative accommodation but don't take him in.

I’m astounded you allowed a troubled 19 year old man who uses drugs and has been accused of sexual assault, move in with your young children. It’s great that you own the house - it means you can put your children’s safety and well being first and put an end to this nonsense situation. Hard no to the step son moving in and I’d be sending the ‘partner’ after him.

Imagine having the audacity to move into a house entirely owned and paid for by your girlfriend then telling her that her 18 year old son who is studying for exams can move out and live somewhere else because he’s a man now - in order to make space for your own layabout son who is OLDER! Honestly OP, see him for what he is - gross.

I moved 60 miles to rent and live with my DD20 and support her through uni as she needed a lot of help. For different reasons, your DSS now needs a lot of help, and what can happen is that his father can get a flat with him and the two of them concentrate on DSS's life and needs for a while (exactly as I did with my DD); he comes back to see his other DCs as much as possible then eventually helps his own son to rent or live independently. When you are a parent, you do the hard shit. Or rather, at the moment, your DP needs to do some hard shit, could be the making of his son.

Although I do suspect that that he was hoping you'd be doing it for him. Where do you want to go from here OP? Your partner has shown you who he is, would it be a blessing for them to move into a flat elsewhere?

Agree with PP who say they would not let this young man into their house. The behaviour he exhibited at his mum's will be repeated and you need to protect your children from that. It is commendable that DP wants to help his son -- but frankly, not in your house.

I can’t believe you agreed he could move in. What were you thinking?

DP: DS has been kicked out of his mum’s for abusing drugs, being violent, abusive, lazy, accused of sexual assault so he’s moving in

You: over my dead body, this is my house, it’s full, he’s violent and dangerous and we’ve got young kids we need to keep safe

DP: you’re so mean and horrible, this is a deal breaker and I’m moving out

You: my priority is keeping the kids safe, get lost

Come on, you hold all the cards. He needs to fuck off and take his loser offspring with him.

why would your DP allow a weed smoking, thieving man into the same house as his young children? I'd ask him and his father to move out

This.

Given your updates, the solution to this is beautifully simple: your P and his son go and get a place of their own. It's your house - I wouldn't have DSS in it, period, and your younger DC are used to having their dad live elsewhere anyway, evidently, plus it sounds like your relationship is still not that great or that stable, so.

Would you also want a man who is aggressive, steals, smokes weed and was accused of sexual assault sharing with a young child? Sibling or not?

Sharing a dad won’t and doesn’t stop sexual abuse.