Step siblings away from each other!

Keeping step kids away from my children. I’m an arsehole I know complete and utter arsehole however I have a 1 year old ( who is starting to talk) and a newborn baby…. Step kids are partners children so my childrens half brothers. They come to my home, swear, disrespect any adult that walks into my home this is my mam included, jump all over the furniture, tell me “ I’m not the boss of them” when my partner leaves me looking after all 4 children on my own whilst he goes to work… this is 4 weeks post c section may I add, the 5 year old has started hitting my 1 year old, they fight with each other this is on the sofa where my mum was sitting holding my new born baby and when I told them to stop 15 times they went home to their mother and their mother phoned their dad and told him how dare I shout at them and take their devices off them! 🙃😂 I seen this thing that said “ keep your children away from children who aren’t parented” and it’s the most truest thing I have ever ever read, because if for a second my partner thinks that im bringing my children up to behave like his children then he is very very very much incorrect. I have told him that every other weekend me and our children will be staying at my mums and him and his children can stay at the home and do whatever the hell they want considering my partners parenting skills are just as bad as their mothers. I don’t need people commenting saying I’m an arsehole and that I’m not putting my children’s feelings into consideration, matter of fact being In the future my children will thank me for keeping them away from their half brothers because they are going to be so out of control, might be funny to their mother and father now but trust me it won’t be funny when they are 15 years old. 😡