You must have a black candle which you light. Pick up the black candle and say 8 times on eight consecutive days:
"NAME
xAbuse of me must stop,
xHurting me must stop.
xNAME must go out of my sight."
As the flame burns down, say:
"All NAME’s power over me has gone. I shall be free from harm."
On the 8th day, after finishing the ritual, wrap the black candle in a black serviette and bury it.
NAME is the person who is abusing you.