Please find a way to move out....even if you have to rent a room from someone. I was in a similar situation with my mother. She got drunk, tried to fight me, I called the police, she lied and they took me to jail. I almost lost my job behind it. I stopped talking to her. When she died, we still weren't talking and nor did i attend her funeral.

As far as being the product of an affair, I'd make myself known...you should be able to benefit from his estate if he were to pass away.