TRF- I love the tone of your post. It seems that you've really turned a corner. Good for you. There will be bumps in the road. There always are. Just try to not let those bumps derail you. Keep going. Eyes forward. Focus on the goal.
As for your marriage, you know I still hold out hope for you guys. Your wife married you and had children with you for a reason. You were once that guy for her, and you can be again. The kicker is that you can still be responsible for your happiness and make sure you hold on to that, and be the husband she deserves.
IMO, the way we gain the most inward happiness is to do for others. Is there a better feeling than watching your kids open their presents Christmas morning? Shower your wife and kids with your love, and you will get a sense of happiness you never dreamed possible. And odds are, they will return the favor.
It sounds as though over the years you made it really hard on those closest to you to stay with you. Now is your chance to make it even more difficult for them to leave you.
Good luck, TRF.