Your mother has given you a miserable childhood but it’s up to you whether you let that ruin your life. Not everyone gets the mother they deserve. When you were little, the lack of a loving mother felt desperate. But you’re 14 now. You are no longer dependent on your mother. She can no longer push you around physically. Your dad has given you another place to go. Most important, you are lucky to have your stepmother in your life.
Stepmom is the counter-model to your biological mother. If you let her, she can give you the nurturance and guidance that your own mother can’t. Instead of torturing yourself with goggle-searches, why not put your energy into making the best possible relationship with stepmom? It won’t be perfect. It can’t be. It doesn’t have to be. All she needs to be is a “good enough” mom and you have what most people have.
If your bio-mom heals and comes around someday, you can include her in your life as well if you like. Just don’t deprive yourself of an alternative “mother” in the meantime. Working out a relationship with a woman you see as normal is your best insurance that you won’t grow into being an abusive person as you fear. It will also give you the experience you need to relate to others who have a more “normal” mother-son relationship.
You are a smart and sensitive guy who thinks about things that most 14 year olds don’t think about. If you do your part to make a functional family with your dad and stopmom, you’ll be okay.
I wish you well.