I work with the elderly and often ask their advice about life issues. I hear repeatedly that they have come through such awful times because they "had no choice". I believe that's the real answer. Not "one day at a time", but finding strength, help, forgiveness, all the good things...where ever you can. Because we are stuck here doing this without a choice. We love our partners, but the disease takes them from us mentally and emotionally first before the physical person is gone. It's lousy.
Two practical things that help me get through are, first, a book called "The Book of Joy" by the Dalai Lama and Reverend Tutu. It teaches perspective, humility, humor, and acceptance (a really big one there!), forgiveness, gratitude, compassion, and generosity. When I can't sleep (most of the time), I try to receive these ideas and think about them. It'll relax me enough to sleep.
Good luck with your journey. I'm so sorry you're faced with it.
The second thing that helps is getting away. I visit my brother who is dying of alcoholic liver disease. He lives in another state, but I fly out, arrange for friends and relatives to check on my husband, and I check on him, too, daily. It's stressful, but it gives me another perspective. I feel much more like myself when I get home. I'm stronger and more able to deal with all of what is going on at home.
Again, my heart goes out to you. You have it rough. Give yourself permission to do whatever you have to to keep him safe and yourself safe.