I am so sorry this has happened to you.
My (f) best friend had a deep depression 30 years ago. One night her husband phoned me and I drove to their house to find he had barricaded himself in their kitchen and she was in the process of breaking the door down. She had beaten him black and blue and, yes, tried to choke him. She is 5 foot and he is a 6 footer, but he 'didn't want to hurt her' so didn't defend himself. My appearance at the front door snapped her out of it. I swear she would have killed him that night.
As soon as she gathered herself, she asked me to take her straight to A&E. I did, and they transferred her to a mental health ward, then a unit. She was treated for a few weeks and released, with ongoing help. They are still married and she has never laid a finger on him again. She had never assaulted anyone before or since.
They have been married 35 years now, with kids and grandkids. She still suffers with her MH, but knows the warning signs to up her meds and speak to the GP. I've known her since we were 5, so 47 years, and I've never known her hurt anyone. She has zero recollection of anything that night, until waking up on the ward the next day.
I say this because a snap is possible, HOWEVER, my friend immediately asked for help. To this day she cries when she speaks about it and it is the biggest regret of her life.
What is your husband doing? Has he beaten a path to the GP's door asking for immediate help. Has he taken himself to A&E? A black out is a serious medical issue.
I fully believe it is possible for anyone to act out of character once. I also believe that it is their actions afterwards that show whether it was really out of character or not. If your husband is truly going to do 'everything in his power' he needs to be DOING that now, not TELLING you. Actions, not words. If he's doing nothing, you have your answer.