There you go!! You're starting exactly where I did last April. First thing I had to do was trade in the joint car and get something with only my name on it. Be careful b/c you will need your AH's signature on the title to sell the one you have now. I didn't have any discussion with my AH about the car - until I put the title under his nose and said, "Please sign this. I am trading in the SUV for a smaller more fuel efficient wagon." He had a few beers in him so he didn't ask any questions. It may have been sneaky on my part - but I did what I had to to get my plan in place.
I did not divulge any of my plan to my AH. Nothing about the car, my new job, the house I was renting. None of it. It wasn't up for discussion with him and I didn't want him accusing me later on of trying to manipulate/blackmail him into sobriety... and I obviously didn't want him trying to get in my way!!!