3 year old nasty stepson.
So I've been in my stepsons life just before his second birthday, his father and I are getting married next year and I have two children of my own aged 2 and 1.
My SS has had a few troubles at nursery, his dad has had to go there with his mother several times to speak to a behavioural psychologist because he had been hitting out and not listening to his teachers.
Now, over the past few weeks he had calmed down. We see him every weekend and he had been fine for a few, but he didn't see him one weekend because he went away with his mum on holiday, so we got him the next weekend and my goodness I could have slapped him. It was a Saturday and his dad had to go out for something important and was gone for a number of hours. And he did EVERYTHING wrong. Hit my daughter while I was changing her nappy, crawled over my youngest child and forced her head into the floor, told me he didn't love me anymore, threw sand in our neighbours eyes, on purpose, hit my daughter while she was having a nap, backchatted me. And everytime I asked him why he did something, the only response I got was "I don't know"
Now, on the Saturday evening when my partner came home, he had a very, very firm speaking to from him and put on the naughty corner. As I was taking my neighbours kids home, I could hear my daughter screaming down the street (She's very vocal so I put it down to a tantrum) but I carried on taking the other children home, when I came in, I could see she was in pain, so I scooped her up in my arms. That's when my mother who had been round at the time told me, that SS had ran over to her and forcefully shoved a juice bottle in her stomach. Now I don't know what happens when the kids go to bed as they have to sleep in the same room so I'm fully aware that bullying takes place and we can't see it.
I'm at my wits end with him and I can't stand seeing my children being hurt by this little brat! I must add that his dad does discipline him very well and by the time he leaves to go back to his mothers house he's as good as gold, but when he comes back again on the Friday all our hard work has been undone!
Has anyone else had a SS who acts like this and how did you deal with it? I really don't want to step on his mothers toes. 
IDGAF if hes 3 or not...this
IDGAF if hes 3 or not...this ^^^ keep that brat outta your house before God forbid something happens to your babies!!!
Where the heck are all of the
Where the heck are all of the adults??? How is it even possible for a 3 year old to have enough time alone with a 2 and 1 year old to keep hurting them?
If the kid keeps hurting the 2 and 1 year old, why do you have them all sleeping in the same room????
Yes, the kid may be out of control, but the adults in charge are making ridiculous decisions.
Why are you living there? I'm
Why are you living there? I'm assuming you do because the kids all sleep in the same room.
Coming from a stepmom who has
Coming from a stepmom who has a four year old stepson who only acts like what you describe rarely (if that), it sounds like the kid is trying to get negative attention from which ever adult will give it to him. The biggest thing with smaller stepchildren is the need for consistency. Each and eery time he is bad you must put him in time out or as we did to bed. Our motto here is "if your listening ears are too tired to work properly then you must need a nap". At three and four years old the biggest punishment would be missing something or being ignored so give him a nap time whenever he misbehaves, eventually he will get tired of having to spend the day in bed doing nothing while the other children are playing nicely together. Another thing is: how often does your SO spend one-on-one time with him? His kid is three and then you have a two and one year old which both need almost constant attention. Where's this boys attention? At three thats really what they want. I would advise your DH to set aside a day (or if there isn't that much time in the day just a few hours) where they do something just the two of them. My DH has always done this and when I had Biobaby last summer I also put a day aside for him and I to go do something one-on-one while my mom watched the baby. We would go hiking or to the waterpark and his dad would do the same when he got off of work on Friday. Another bit of help I can give you is that three year old love to be "little helper" so if you encourage the boy to help the younger ones or help you with the younger ones then his whole mindset of "hurt them for attention" should change to "help her with the children for attention." For every time you give him negative attention you are feeding the little monster. You need to double the praise when he does something good and immediately punish him to his room/timeout/whatever every time he hurts another child or talks back.
I have a 3 year old son who
I have a 3 year old son who isn't at all like your step-kid behavior-wise, but I felt this awful sadness for him. He really needs help. He's clearly unhappy and he probably needs professional help. He's had massive changes in his very young life-that can be very disturbing to a little kid. I think when little kids have to go between homes it can be totally awful for them, and no one seems to care about how they feel if it goes against what the parents agreed to, custody-wise. I totally, 100% support you in whatever you need to do to keep your baby safe, his mental illness/physical illness/behavior disorder is not your fault. But he needs therapy, stat. Try to be gentle with him and remember he's just a baby. A really messed up baby.