Update:
Well Sr friends, I did it. Just sent the bank the assumption letter for the credit card and got the dissolution papers notarized and in the mail.
I realize now how crazy this all is, as well as how many signs of relapse there are waving right in front of my face. If he's not drinking, he will be soon. The conversation we had over email this morning was baffling and sad, on top of more blame and a serious case of denial.
It's worth the financial loss to get away from this madness. Thanks all for your thoughts here. I appreciate it very much!