My AXBF lost a place to live (rent-free with no bills), a girlfriend who loved him (for ten long, drama-filled years), and a newborn daughter. He chose alcohol over us, and it still baffles me.
We see things clearly because we are operating in a very harsh reality. We expend so much time and energy thinking about the situation every day: what it means, how to fix it, whether to fix it, etc. They, on the other hand, operate in a fantasy land where alcohol fuels the lies they tell themselves. They expend their energy on getting their next fix. I know it's hard to stop the hamster from spinning in that wheel in your brain, but there is no making rational sense of their behavior; it's like squeezing blood out of a turnip.
I'm glad to hear you're taking steps to get out, even if you're only thinking about it and not ready to do it. Baby steps. Take care of you.