Absolutely, I would not to give him a second chance. I had been going through verbal and physical abuse for 12 years during my first marriage. I gave him many second chance but he never changed. Also, he had been affair bunches of women. I gave him other chance. He never changed !!
At once - someone who abuse you. He/she would never stop
someone who affair/ cheat on you. He/she would never stop
someone who stole your money or credit card. He/she would never stop.
I would go to the court to get a restraining order against your step-Dad to stay away from your mother and family. He is worthless. He needs alot of help to see a specialist psychiatrist. Your mother needs a lot of your support and protect. Divorce Tony !!