How do you forgive, when you been hurt too many time?

For years, over and over this family member has hurt me. even though the years of my continuous help I given to this unappreciative person. I'm looked at as the bad one. because, I'm tired and I decide I'm not taking it anymore and not speak. their crying hurt, I'm wrong...wrong, I don't think so. like I said the years of my continuous help..not one time this person help me to help their futures. I made straight lines for this person futures. and in return they try to turn their futures upside down.they already dim one future.the one light I have left, I want to beam. I was told I was wrong for not speaking. but, everytime I let them back into my life is a thunderstorm.