Hello Matthew,
I'm not going to sugar coat this because it will do you no good and time is short.
What came to mind regarding your wife fighting against things you agreed on is this scripture. 1 Corinthians 6:7
And this one: Matthew 5:39.
I know this may seem radical but frankly it is the way of Christ. Do not resist her. Give her what she wants.
I also have to ask you a question because this statement in your post troubled me: "I know that divorce isn't a desirable thing and if I thought it was unavoidable I would but sadly my ex isn't a Christian and is unwilling to work on any part of the marriage to make it work."
Matthew, did you initiate this divorce? Did you seek a divorce because your wife is an unbeliever and she was unwilling to make what changes you think need to made for you to have a 'happy' marriage? If so, you must NOT divorce. It is a sin and not the Lords will.
If it was your wife who left and filed for divorce have you stood in faith for your marriage? Have you made the committment to show her love and be faithful to your vows and woo her back?
Matthew God does not want you to divorce. There is a narrow way that leads to life and you must find the courage to follow it. This broad way you seem to be on will lead to destruction...for you and for your children.
This is also not only about you or your wife ultimately. It is about your precious children and the future generations. Do not allow the curse of divorce to enter your lives and the lives of future generations. Contrary to what you may have been told the evil divorce causes gets passed down for many, many generations...and it is NOT pretty, but horribly devestating. If you are not experiencing that yet in your life or your childrens lives, believe me you will at some point.
I am very sorry if I am wrong on your situation. Please forgive me and I do not come to condemn you. I speak with urgency because something seemed a little off in how you described the divorce, (you should be praising God your wife arguing about matters has slowed the divorce down! This should give you time to fast and pray for the restoration of your marriage) and because it seems time is of the essence I just had to be direct with you.
I am going to be praying for you, your wife, your marriage and children.
Don't give up Matthew. Don't believe the devils lie that the grass is greener on the other side. It isn't. You have been blessed with the priviledge to display the love of Christ to an unbeliever, who happens to be your wife. If you follow Jesus way, it will be a powerful testimony to the Lords glory. Who do you love the most? Jesus or your own 'life' in this world. That is the choice you must make, and more than your marriage depends on it.
Bless you and praying for you.