One of the first things we , I,  was taught upon entering Hendon Police Training College many moons ago (late 1960,s) was the fact that you never became involved in any domestic disputes twixt man and wife or family members in general . In the event of women fighting you kept well out of the way.

The reason being that in 95% of the cases the protagonist's would unite in their anger and turn on you the solitary copper.

Wait,in those days anyway, for a Black Maria to arrive with reinforcements and a first aid kit!!!