Can’t manage her mood swings!

What do I do about my girlfriend’s mood swings? She is kind and loving on some days, and completely unreasonable on others. I used to let this go because I assumed it was just her personality, but we have been together for almost two years now and it only gets harder for me to cope. I have tried being patient and even avoid meeting her when she’s not in a good mood, but it’s not an ideal scenario for a long-term relationship because I am constantly on edge and feel as if I have to be extra careful around her. She knows this is a problem but if nothing changes, I won’t be able to stay with her for much longer. How can I resolve this?
There may be all kinds of reasons for why your girlfriend behaves the way she does, and mood swings may not be an adequate description. If she is struggling with something, and doesn’t have the tools or coping mechanisms, her actions may be a cry for help more than an act designed to cause pain. It’s important to have honest conversations about why someone behaves the way they do, and whether they understand how they are affecting others. If being with her is compelling you to not be yourself, this is not a healthy environment. If she accepts that and wants to create a space where you can both feel more at ease, she may need to speak to a professional who can guide her. Tell her why this is making you question this relationship and why it can’t carry on for much longer and talk about what you can both do to address what is lacking. Sometimes, fixing what is wrong starts with being able to identify what expectations you both have, and what isn’t being met.

I don’t know how to end my relationship with my boyfriend because he says he can’t live without me. What do I do?
Accept that the onus of managing his grief isn’t on you.