What you described in your post is almost exactly the same story as me and my wife's (down to the dishes and the suicide thing).
I'll make this short. Your kids are right. You didn't cause it, you can't control it, and you can't cure it. You can, however, contribute to it and you have been doing just that by being her enabler.
Here is what saved me from myself:
How to find a meeting in the US/Canada/Puerto Rico
Go to at least six meetings, some different, before deciding if this will work for you. I believe with absolute certainty that if you fully engage with Alanon your life will improve markedly and dramatically. You will be a happier person. It will also help you make better decisions about when, how, and if you should engage with your wife.
It won't heal her. It's not for her. It's for you. For her there are other programs, including AA, that may or may not work, and won't even have a chance to do so unless she fully engages with them.
I really hope you go to Alanon and give it a fair chance. I suffered needlessly for years because I refused to go to a 12-Step program. My ego was too big, and I thought I could handle things myself. I was wrong. It turns out I'm just a regular guy. Unless you are Superman, Batman, or some type of God, you are just a regular guy too.
Take care, take what you want, and leave the rest.
Cyranoak
P.s. Noday is right about everything she said. When my wife threatened suicide I called the Police. She spent the night in a psyche ward and never did it again because she knew I'd call the police again. I suggest if your wife ever does it again you call the police. You are, in fact, being held hostage not only by her, but by you.