I think what he means is that anyone married to an abuser chose to be married to that person. Some people promise to love "in sickness and in health". Abuse is a sickness. What he doesn't know is that some people hide who they are. He is a sweetheart courting but after marriage he proves to be a snake.
Not many people choose to marry an abuser. They get tricked into the marriage. Therefore, I think God would call separation from such a person an annulment. You did not marry the man who would abuse you! So by God you may remarry.....but be more careful next time.