Just to reassure you that my older brother and I fought and argued 95% of the time growing up! When I say fought, I mean we physically kicked, punched, slapped, pinched, pulled hair, Chinese burns and it was to hurt not to play! Now we are older we get on really well and I ask him for advice and we can both laugh at ourselves.
We were pretty awful to our mum as well, we argued over everything with her and never helped with cleaning or chores and would rather argue for an hour than do a 5 minute job.
How we all survived I don't know. I also don't know what the neighbours must have thought with the constant screaming and shouting!
I think if it was me, I'd get the kids out of the house so I could have a proper chat with DH to write down some house rules.
I think once you can impose the rules (be consistent), the kids may be angry with you, but you might find they join forces to whinge about you and they'll find something in common?!