Jane this is a tough decision to make for anyone. For me it wasn't so much 1 thing that broke that camels back. It was years of trying. I think you "just" know when it is finally over. There is a feeling that you have done all you possibly can to save the marriage. For me it was when there were no feelings left for the most part. I have had a couple of marriages/divorces. One was an abuser the other an alcoholic. Both were very difficult to make that decision. pm if you need to hon.