New to all this. Have a behavior problem and a few questions.

Hi guys. I'm a male, 29. My girlfriend is 35. She has 2 kids, boys 6 and 8. We have been together for 2 years. I've lived there for almost half that. Please don't focus on that part. I know moving in too soon is bad but we are fine there and I don't think that really has anything to do with the kids behavior. Me and her are very much in love and are best friends. She just helped me when I was in a bad spot and I thank her every day any way I can. Ok.. so these kids.. they are verbaly abusive to me, her, grandparents. I'm sure where their dad gets them they are shitty to him and his side as well, don't really care about them really tho. Alright. So we ask them normal things please brush your teeth, get dressed, it's time for bed, ect.. example from last nite. Me to the 6 year old. Hey man turn off the tablet it's bed time. No response. Please do what your mom says .. no response. Hey man I'm asking nicely, what did I say the other day about doing what we ask? He says. Hold on I'm not done leave me alone. Me: no it's bedtime. I said now. This is why we get mad and yell. You guys don't listen to anything else.. him: SHUT UP! I SAID IM NOT DONE! Me: yea youre done. I take the tablet, and he gets up and screams you are fucking shit Jesse! And tries to hit me.. I was called fucking shit a few days ago by the same one. The older one is the same way. Calls his mom all kinds of names hits her in parking lots. Me as well. Everything is a screeching girl scream argument. Dinner is never good enough even when we know they like the food. Nothing is good enough for them and they are always fighting and screaming. That's pretty much how we wake up every morning. Either them fighting or the little one screaming and hitting his mom because she said he can't have the tablet cause he didnt behave the nite before. Ok those are some examples. I have never hit and never will hit them. She spanks them and then cries about it later to me. Not even with a belt. Just her hand. She actually slapped the older one in the face today because he hit her in the face with a soccer cleats. She went to bed before I even got home cause she's so messed up about that. I feel so bad for her.. ok. So punishment.. we take away their computers. Put them in their rooms. They just come out or climb out the window or something. They don't care about threats. I won't hit them and when she does they cry and then they are back at it. There is nothing we can do and it's killing me. I cat sit here and watch her keep getting disrespected. I don't care about me. She is so good to them. They always get everything they need and want for the most part. She gets so depressed about them treating her so bad. Please.. if you have any advice that would be amazing. I'm at a loss. I'm thinking scared strait or taking them to the cops next time one puts their hands on anyone.. also the next time I get called fucking shit that kid is gargling dawn dish soap. If I had even said shut up to my mom I would have been gargling my teeth instead of soap.. thanks again for reading. Means a lot to have people to talk to.. via /r/Parenting http://ift.tt/2eaevTd