I recently encountered some interesting information on violence.  According to Vivian & Langhinrichen-Rohling, (1994) 85% of couples say physical aggression goes both ways, so there is frequently a counter-attack.   Stets & Henderson (1991) also found that, in intmate male-female relationships, the woman is 14 times more likely than the man to throw something and 15 times more likely to slap.  Of course, women suffer far more injuries when physical aggression does occur.