I agree with your plan to discontinue joint accounts with an active alcoholic.
I did the same.
I was not the primary on the joint account. (In my state, at my bank, the person that signs first on the joint and issues the first SS# is the primary person on the joint account.) I could not close the joint account. I could take my name off the account and open my own account, however.
I had to have my husband (as primary) sign to close the account. He chose not to close the account.
Next, I put a block on my personal checking and savings accounts. The block means that I can not call and get my balance or any other information on my accounts. I can not order checks over the phone. I can not call and order a replacement debit card over the phone. I can not do anything to or learn anything about my accounts via telephone. I must do all my banking in person by showing my I.D. ( I do direct deposit, so it really is not inconvenient) I can, however, do most of my banking online with password protection. I put my account on block status because my AH knew my SS#, Date of Birth, maiden name and mother's maiden name.