Well, I will answer your direct question of what do you do.

Either be stronger, or leave. Decide what you want/are able to do.

As someone who also has wanted to die, I can tell you that she probably is not taking those meds. She may not be seeing a doctor either.

Depression is exhausting. She probably has no desire to help herself at all. Don't trust her to.

It's up to the individual (you) to decide how much of yourself you can give. If not for my husband, I would not be here. Even today, now that I am kinda okay/kinda horrible as opposed to just plain...nothing, I would have no ill will toward him (speaking strictly from a relationship viewpoint) if he called it quits. I would understand.

I am sorry you are going through this.