1. If she doesn't have a Green Card. Immediately withdraw the I-864 before the I-485 is approved.
2. If she already has a Green Card, my advice is to Finish the divorce, move on, and seek happiness for yourself. Hopefully, you have a good attorney. It is probably in your best interest that she becomes a US citizen as soon as possible. You are obligated under the I-864 until either she becomes a US citizen, loses her LPR status, gains 40 quarters of work credit, or dies. Actually, there is no 10 year limit.
Remember, you submitted a great deal of evidence showing the marriage was bona fide. Marriages go south every day. If she entered the marriage in good faith, you have no case. I wish you well and I hope you can find peace.
***Moved to Effects of Major Family Changes On Immigration Benefits***