What do you do when you finally discover that your dad was playing your mom all those years?

He has the character, manipulation, and my mom is a very basic woman who gave out her whole life just because she did not want to ruin her marriage and end up a dysfunctional family. She loved him, because he used to trick her, he cheated on her threatened her to leave her. Those ****** up tricks and she fell for because she never dated anyone before him. STUPID. he never actually did anything like buy a house, or pay our tuition at school or anything relevant. He just was there living the dream. Shes an angry woman, she never ever traveled or did something for herself because of him. What would you do ?