We do what we have always known from our parents and other family members being the role models to look up to.
If our parents were in abusive relationships and we grew up hating the fighting and the harsh words that forever scar, there is a good chance that the children, even though they hated it, will repeat the behaviors later on in their relationships with others.
Grown children of alcoholics, drug users, abusers will likely be more apt to take on their parent's behaviors and habits then those that didn't grow up in a home with those factors.
"I have become my dad (or mom)" is often heard from many children around the ages of late 20's or early 30's. Just when they are settling down with spouses and children of their own.
There is also a large amount of blame for their own behavior onto the parent themselves. Lashing out, not taking ownership of their own actions and not realizing that they are repeating the cycle.
There are many roles that children fall into growing up in an abusive home. The "over acheiver", "the rebel", "the attention seeker", "the promiscous one" seeking out love from others and feeling more helpless when that does not satisfy their needs. Many have alcohol and drug addictions, themselves and will often times, call the parent while intoxicated and vent their anger at those they blame that "made me this way".
Early recognition and counseling with an objective person is very crucial to ending the cycle in the family. That is something that each individual needs to come to themselves and truly want to change for the better. When that is done, chances of passing on the same traits as the generation before, will cease.