Mona, It's true, you didn't waste 20 years of your life. Take a deep breath and look around you. Look at what you've accomplished and you did a large majority of this on your own. Trust me when I say this, if things hadn't been great, one of you would have left the marriage a very long time ago...that didn't happen. You fought for your marriage a few years ago and now you are doing the same...but this time around you are a far wiser woman and know what you need to do sooner.
You've got a lot of living to do still. Sure, the current chapter of your life has the print smudged a bit, but the rest of the book still needs the pages filled to the brim w/what is going to transpire in your life. Live your life to the fullest and be a good role model for your kids. You are so right about the 20 years you spent w/your h, i.e., it is no time at all compared to what you may have left to live until the end.
It's okay to leave the door ajar and continue moving forward. If the dumb cluck wakes up and realizes that he's lost the most important person in his life, he may opt to paddle harder to catch up w/you. If he does, he's got a lot of hard work to do to earn your trust, faith and love back. Don't make it easy for him...he's got to prove himself to YOU and no one else.
I think you need to take some time out for a nice spa day. A nice massage would be very good and while at the spa, get the works. You owe it to yourself. Sometimes we have to pamper ourselves in order to get our batteries recharged and I think a spa day would do you a world of good!
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.