violent conflict between parents..!?

It has become almost a everyday situation for me and my sister, that our parents often have some (sometimes even violent)arguments because of nearly EVERYTHING.

My father always (!) tries to make my mother's life stressful and difficult and she lets him provoke her (He knows exactly that her habit is to get quickly stressful -> provokes her with her "faults" like "Why do you cook so much, I can't eat all of that; just so stupid, not thinking about his children or her and who said that he has to eat her stuff,just to feel like provoking her after he ate).

If my mother's not at home or if I have involved myself to mediate their disputes he then does the same with me.

I'm honest, most of the time I was just thinking about how to BEAT him up (I'm a martial artist;Taekwondo) and let him suffer everything he did to her, but that wouldn't really solve anything.

Reputation is very important to both of them, that's why they were thinking about divorce, but none of them would do that (Reputation).

The other day my mom found out that a friend (!) who was divorced since a year has a go to bring her to apply for a divorce, just to "snatch" my father away from my mom (Sorry, but that's what I call a bi*ch).

Everytime they argue with each other, my sister and I aren't able to even learn for school (test and so on).

On top of that my father said (when he wasn't careful about what he said, he confessed that if they (my mom and him) are divorced, he would immediately MARRY that KIND of "friend" of hers (that b**** you know)

I always knew that my father doesn't love my mother at all (when they married my mom was pregnant (my elder sister) and he was even DRUNK at that night and he ordered her to sleep on the FLOOR with only a thinny mattress).

Normally I wouldn't tell this to anybody (except my friends) but I don't know what to do since my mom wants to suffer until my sister and I have graduated to move to a good friend (and not someone like the other "friend) of hers.

Calling the police or trying to arrange that with friends didn't bring anything at all (my father pretends to be a "good" husband when there's somebody at our house, but when they're gone his real "face" appears again)

I just don't want to see her suffering because of a pitiful a*shole.

Sorry for the long text..