She threatens to hurt me!

My girlfriend is emotionally unstable, and this is making it hard for me to stay in a relationship with her. I am worried about ending it for the same reason. She threatens to hurt me, says she will never let me live in peace, and wants me to marry her because we have been together for two years and she believes I owe her this commitment. I don’t know what to do because I am so afraid of what she might say if I walk away. My mental health is in tatters, and my friends believe I am hurting myself with every day I stay in this situation. It is just fear that prevents me from ending what is anything but a stable relationship at this point. How do I get away from this without worrying about what she might end up doing to herself or to me? I can’t think of a solution.
You aren’t helping yourself or your girlfriend by being in a relationship that has run its course. If she is unwell, and needs help, you don’t have the tools. No relationship can survive on fear, and your reasons for staying aren’t compelling at all. Your girlfriend may threaten you, but anything that causes you genuine harm has consequences despite what she may say. The best thing to do is get someone you both trust involved in this conversation and talk about why it isn’t working out. If her family or friends are aware that she needs help or emotional support, they can then do what they can to give her access to professional help or advice. Staying on at the cost of your mental health doesn’t do any good for either of you.

How do I convince my boyfriend to take responsibility for his actions?
Assuming he’s an adult, you should call him out and ask for an explanation or accountability because you are entitled to it. If he doesn’t acknowledge it, there’s a problem because he isn’t taking you seriously, which is disrespectful.