Hi, I'd like to help you with your question.
Getting a backbone sounds good, but in reality it is not the answer to your problem. Understanding what you are going through and why can help you find better ways to cope and ultimately leave the situation you are in if you desire to do so. But the only way to do that is to work on your own self esteem.
It sounds like your partner is abusive. Anyone who yells and screams at a person and puts them down is abusive. If you are feeling broken in mind, body and spirit then you may have been abused for a long time. When you are exposed to cruel behavior that long, it can make you feel like giving up because it erodes your self esteem.
You are stronger than you believe and by focusing on that can help you find your way out of this situation. Start by learning what you can about abuse. See if your situation matches the symptoms of an abusive relationship. Then take steps to get yourself out. There are a lot of supports to help you. Here are some resources to help you:
The Verbally Abusive Relationship: How to recognize it and how to respond-
If you find that your relationship is abusive, getting support can make a big difference. Consider joining a support group on line or in person. Contact your local domestic abuse shelter for ideas and options. And try therapy. It can help you overcome the issues that keep you in the relationship and provide support to help you move on. To find a therapist, talk with your family doctor. Or if you attend church, your pastor may be able to offer low cost or no cost therapy. It can make a big difference when you have others to talk to.
I hope this has helped you,