Alimony Modification in Ga?

Ex makes more money now than we got a divorce, Im still paying her alimony and will continue for another 6 years. I need to know if I can have it modified, terminate it or have it reduced since she is now making more money than when the court order took place. She cheated on me, thats what initiated the divorce, I was the one who filed it but I got screwed, ended up paying her alimony instead. There is no justice! Im also paying child support for our 3 kids which I dont mind because I love them dearly.