So I don't drip feed I will add some background, sorry if this is long. There is much more to it but I'll try to summarise.
My DP has one child from his previous relationship and we have one together. DSS didn't take the news that DP was in a relationship with me very well which wasn't helped by his mum lying saying I was the reason they'd split etc. All through our relationship his mum has been trying to turn DSS against DP/both of us. Neither of us are perfect but we love DSS and none of what his mum is telling him is true. He was 10 when DD was born and she started telling him DP didn't love him anymore which made him resent DD a lot and would try to hurt her, when she started walking he'd push her. DP tried and tried to rebuild the relationship but it didn't work.
He's not been here since Christmas. Since then he's been refusing to come, DP has tried asking if he wants to go somewhere else but he gets ignored. He turns 17 near the end of this month.
Just before his birthday ex messaged him and told him he was having sex with girls (not a girlfriend) and he needed to talk to him. He went over there and tried to speak to him and gave him a box of condoms. He didn't listen and told DP to leave him alone and to stop getting involved in his business.
Yesterday ex messaged DP and asked to pick DSS up as he was still inviting girls round that she didn't know and she caught him having sex and if she did then her younger children could've. He told her that he was going to carry on so she sent him here.
He was angry as soon as he got here but he was made worse when he realised that DD has his old room and he's in the box room. DD is 6 and had a lot of toys which wouldn't fit in her box room so we thought it made sense that DD took the bigger room. DP agreed.
He was shouting and telling us to fuck off. I went out with DD. DP later told me he didn't calm down and told him it's up to him what he does and no one else. He stormed out and wasn't answering his phone. This was about 5pm. We were both worried but he came back around 11, very drunk. DP dealt with him. But DP now thinks maybe we were a little unreasonable in swapping rooms without DSS knowing and thinks we should maybe switch them back. I don't think we should as he’ll then think having an outburst will get him his own way and we wouldn't have done the swapping if he was coming here regularly. AIBU?