Thank you for writing. The best time to deal with issues like these is when you are young.
From what you wrote, it sounds like your mother has a pattern of marrying bullies. Her choices are her issues, not yours. It becomes your issue because you have to live with them.
Since you are only 15, you can’t leave physically but you can withdraw from the fight. No one wins in a fight with a bully. It’s pointless to try. Your stepdad is entitled to his opinions and you are entitled to your own. You aren’t going to bring him around to your point of view so why bother trying?
To resist the temptation to fight, stay away from your stepdad as much as possible. Join a team or club that meets after school and on weekends or sign on for some volunteer work. Get busy with homework after dinner.
I don’t think you should give up on talking to your mother if her husband bullies you. If he ever — ever — lays a hand on you, you need to report it to her. If your mother doesn’t listen, you absolutely need to talk to an adult at school. No kid should ever be afraid of an adult they live with.
All men are not like your dad and step-dad. Do study men in your life who can offer a counter-balance. There are probably male coaches, teachers and fathers of friends who are very different from what you’ve experienced. Think about positive examples of men who treat women and girls positively. If you are starting to hang out with boys, don’t put up with bullying for even a minute. You deserve better. You may not be able to choose the “fathers” your mom provides but you absolutely have the power to choose a caring, supportive and sensitive boyfriend.
If you can find a way to get some therapy (now or in the future), it might help you be clear that none of the things that your father did are your fault and that you do deserve a good relationship in your future.
I wish you well.