I'm sorry about the situation you are in, but glad to read that you are taking control over your life and doing the right things.
I don't know if others will agree with me, but I would consider your secret drinking and spending on joint credit cards as a form of infidelity. She may know a lot more about your drinking than you think. So perhaps in her mind, you have cheated on her with alcohol and betrayed her financially. That could help explain where she is coming from. For you, an affair with another person may feel very different, but to her, you left the marriage before she did.
It's just something to consider when you try to figure all of this out.
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17