How to make the final decision to divorce?

In the past 3 years I have been thinking about divorce. We have seperated twice so I know that if we seperate this time it is over for good. I keep reading tons of articles on the pros and cons of divorce. Many of them focus on the children. We have no children as I am infertile and was honestly the beginning of this downhill slide. It has just created one problem after another. But when do you know its really over?? I guess I am just thinking too much and too worried about life after the papers are signed...help from those who have personally went through this would be great. Thanks.