Dealing with violence and addiction in dementia. Any advice?

Been on this forum a couple of years. Began due to my mom's decline. I am an only and had been slogging along mostly by myself for the last ten years. She's 100, I am 62. She finally went to assisted living and I got a bit of my life back but not for long.
My husband is 72, longtime addict, intermittent periods of long clean time with relapse, currently in relapse. He's been retired for health reasons, back surgeries, COPD for quite awhile, I am still working.
The past couple of years his personality has changed , he's very forgetful and increasingly physicially aggressive and hypersexual. I could not tell sometimes which was running the show, addiction, or what his doctor calls "mild" cognitive decline. His "relapse" is prescription narcotics he gets from his pain doctor, a ridiculous amount in my opinon.
During the worst, most difficult years of helping mom, he sometimes would help me but mostly just complained about how busy I was and that I never had time for him. He joined about 50 dating websites, not the nice ones where you look for your soulmate, but the skeevy ones, the hookup ones. Once I discovered the $ on the credit cards and finally snooped his computer, hell ensued. I was very upset and felt betrayed and he defended his "right" to entertainment. A couple of our interactions became physical. He tripped me one day and shoved me another time. We sought counseling but he didn't see the problem or thought the problem was me and that I should just chill the F out. So we quit wasting $$ on that.
He has continued to decline memory wise, very little short term memory.

So lately, whenever he is angry with me, he claims I am not his wife but some vagrant, squatter taking up space in his house. This happens more toward evening so I am guessing it's sundowning. I feel like I walk on eggshells around him all the time. If I ever, God forbid, lose my patience with his memory issues, his refusal to wear his hearing aids or any age related decline issue he is easily raged and has again started shoving me, twisting my arm, etc. He took off one of my shoes and hit me with it a month ago. I threated to call the police but never did...until last night when he again, accused me of being an intruder in his house. He first locked me out in freezing weather with an inadequate coat. Thank goodness I had my cell. I called the police, he told them I was an intruder , they surmised his condition and told me to go to a hotel or a friend's home or to at least stay in separate parts of the house. I was worried about my rescue dog, who witnessed all this so I chose to stay in another part of the house with her. Stupid of me.
He sought me out and threatened me, so I decided to go to a hotel but he blocked me from leaving. I told him I would call the police again, this time they took him to ER for evaluation but did not put a hold on him so he was free to leave, which he did. The hospital is about 3 blocks from our house so he walked home, really pissed now. I asked if I could leave, he said no and blocked me, took my keys. I was scared so I tried to call the police again. I did try to de-escalate but he has having none of it. I was successful in reaching 911 but not before he bit me and tried to break my arm. He's in custody now.
I know I should have handled this differently, but how? I feel like it's always my fault. What set him off was he asked me if he could have a candy bar, and I said, in a rather exasperated tone- what candy bars? we don't have any. Guess I should have said it more sweetly but I was all outta sweet. While he is there I am going to file for divorce. He has no family that will have anything to do with him and all his friendships in recovery programs have dropped away as he is using. I was his last person. Yet, I wonder what will happen to him. Guess I need to get out my co-dependency books and dust them off, hit an Alanon meeting and talk to an attorney.