Daggers And Words

Why is it that people who claim to love us so much insist on hurting us with their words? Is it because they have been so hurt in the past that they feel the need to hurt us with their words to give us a taste of they have endured? 
I am not sure what the answer would be. I do know that every time we let someone hurt us with their words, we begin to see ourselves in their fashion of hurtful words... And that's when we lose sense of our true selves.