falling back

I am 45. I first wanted to die when I was 18. I had children so that I would be tethered to this world, and I will honor that commitment. I will not kill myself, but I fantasize about if. I slide into the noose. Could I do it hard enough to break my neck? Probably not, but in my fantasy I can.
For 15 years, I’ve been psychologically abused by my husband. It only become physical a few times, because I could control him. That was my fantasy, but I realized that I can’t control him, and he is harming my children with his yelling.
Why did it take me so long to realize? The truth is that if not for my children, I would kill myself before leaving him. This destroys the scraps of my financial life
My question is, Why does the fantasy of my death give me so much pleasure? More importantly, why can I insist that my husband move out for my daughters but not for myself
I am alone. And my kids depend on me. But at my core, I know that I deserve to die. I hate myself.