I was in a bad relationship many moons ago and continually vented about the boyfriend to my best friend. I think I wanted her to be as mad at him as me and to condemn him so I would somehow feel better. Eventually, she was a good enough friend to tell me that I needed to stop complaining and make a decision. She was right. I was allowing myself to be stuck in a rut because I was too scared to take the first step in changing things.
Change is hard and it can be scary. But the alternative is to stay stuck and miserable. So perhaps it would be good for you to start writing an action plan of how to improve your life. After all, it sounds as if he's not going to change and if he makes everyone else miserable, you have no duty to be his doormat. Instead of seeing all the reasons you can't get out, try inventing ways that you can. Lots of good advice about jobs and opening your own bank account, and I know there is something you're good at that might help you connect with a job. Think outside the box. Maybe learn medical transcription or something else you can do from home. Don't worry about the car, it's going to have the same mileage whether you stay or you go.
The worst that can happen is that you will be in the same position thus time next year. And you've got this large group of folks here for support!