In my day, there was no fancy-schmancy "Xbox"! You did your homework and worked in the fields for 12 hours, until you came to eat your evening bread and god to sleep, taking shifts with your 14 brothers and sisters to fend off the rats! And you'd wake up 3 hours later to go to school and do the whole process over! Free-time, ha! Our "free-time" was when old Betsy (Our ol' cow) wouldn't milk properly, and we had to wait til she settled down!
Anywhom, parents often fight, however such violence isn't accepted. As said, you should probably talk to someone close to you and don't add any unneeded stress to your parents. Sometimes parents split up, but you shouldn't stand in their way if they decide to. It would probably be for the best. And who knows, perhaps they may resolve their issues. Maybe just some event is occurring that isn't normal, though a high level stress point.
As for you,perhaps try to pull your weight around the house a little more. I doubt they say you cause all the troubles, but if you only do two things, they most definitely would be bothered. Show appreciation, they do much for you, a lot of which you probably don't even know about. :o