CC, I am sorry that he's letting you and most importantly, your children down. Please keep your expectations at zero. I know you've been doing this and w/the holidays, you had hoped he would be in more contact w/the kids, but he was just too busy w/doing things for himself. I hope that, in time, he'll do better by his kids.
Maybe it would be better if he spent the time w/the kids and you did something else. He's not missing you if you are readily available. Just a suggestion.
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.