George, Good for you, but I will tell you that even with your positive attitude it will still be the most stress you have ever had, but there is life after divorce. Be strong, keep your good attitude, and take care of your son as she will not make it easy once she sees you are willing to leave her! Take it slow on the dating scene and do not rush into a relationship just because someone is attracted to you. I did that because my first wife had me so insecure about myself.
You are correct in your summary that your wife does not like the new more confident you! When my marriage fell apart I was on a very high note with my career and she tried to tear me down at every opportunity. I also was losing weight with the success of my career and the renewed confidence and those things combined gave her insecurity and I saw real hatred directed at me. I also could not believe that someone I loved with all my heart could try to destroy me. In the end I had to find leave the relationship for my own good and you know that once I was free of her it felt like chains were taken off of me! Good luck and remember there is someone out there for everyone, just proceed slowly.