I'm glad to see that you aren't sitting at home mulling over everything that was discussed.
Unfortunately, he is the only one that can help himself and improve his life. Everything he touched on is how a MLCer feels and they just don't get it. The external things aren't going to make him very happy and in time, he will come to realize this as he tries each and every thing to see if it will improve his life and make him happy.
As for dating, I wouldn't. Why? Because it would alleviate some of the guilt he's feeling about dating himself. Stay true to yourself and whatever you do, do not pretzel yourself to try to make him happy. For every little thing he points out that you need to change, once you've done the changes, he'll come up w/another laundry list. Only make changes that you will be happy w/and they can become a part of your day-to-day life.
Your h has a lot of growing up to do and he's going to find out that the illusive happiness over the rainbow just doesn't exist. Happiness comes from within. Please do not drink from the pitcher of Kool-Aid that he is serving. Do not take on his problems as your own, because they aren't. Just remember, if your marriage had been so bad and beyond repair, you would have known about it years ago. He is looking through the rose colored glasses of MLC and until the light of day hits him square in the face, he'll continue to talk the MLC BS.
GA, the best thing you can do is listen, offer no suggestions/advice, unless he asks for it.
Live your life to the fullest and know that you are the prize.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.