Along with me, everyone has been blind-sided by her request to Divorce me. Are there any options to slow-down the Divorce process in order for my wife to taper off of Xanax?
Uuuuum, sorry, but no. You are grasping at straws here, trying to resuscitate a marriage that is on life support and will die anyway. Speaking from personal experience here, I and many others (most?) in our circle of friends and family felt blindsided when my X filed. I was blown away when I discovered how far gone she was before she filed, and the lengths she had gone to in order to jump from one branch to the next.
Your marriage is over. Don't try to slow the process down because it will only cost you precious time, emotions and money (again I speak from experience, I tried that for four months, to no avail). Get used to it, prepare yourself to get through divorce as quickly and with as little pain as possible, and start thinking about your future post divorce.
Xanax doesn't make anyone get divorced.
Whenever you think divorce is bad, remember there are worse things than divorce.