Just my thoughts... I think someone can know they are in an abusive relationship but rationalize it away.
Yes I am going personal here... I won't go into detail the abuse I suffered as a teenager other than to say it was horrid...
So when six months into my marriage when the pushing, slapping, biting, finger twisting (his favorite) started.... did I know it was abuse? Yes.. but I rationalized it away... it could be worse, been through worse, he never punched, etc. He rationalized it because he never punched.
So yes I knew it for what it was BUT... there was that but in my head for years. It came to a head 5 years into the marriage when one night he started getting physical and I had enough and tried to leave... it ended with him choking me in the driveway. <<< It took that to make my husband realize what he had been doing to me and for us to realize this ends here and now.... we need to break the cycle.
That is why I am so for teaching people that the cycle can and does break.