It sounds like you've been doing a lot of contemplation and figuring things out. Thinking that exposing an affair would fix things didn't take into account that something had to be wrong in the relationship long before the affair ever happened, or it wouldn't have happened. If your husband wasn't the type to sit down and talk things out before, there's virtually no chance he'll agree to it now.
The up and down swings of your grief are absolutely normal, as is your feeling that things are left unfinished. That is the nature of divorce. There will never be a time when you feel that you know everything you wanted to know, or said everything you needed to say. When you're able to change your focus from what happened to looking to the future, and how you want the rest of your life to be, the craving for closure will diminish. It won't happen right away, as you're still in the grieving process, but it will fade from importance with time.
It would really be a good idea to get a local counselor to help guide you through this process. It's important to have someone outside the family to vent to. Your children, although they know you were wronged, will still have some loyalty to their father, and venting your pain to them will put them in an awkward position, emotionally. And they may have a hard time visualizing what your new life will look like...so having a new person to help give support, perspective, and inspiration will really help.
Be patient with yourself, and expect the ups and downs to continue for awhile. You've been through a major upheaval in your life, and it will take a fair amount of time to adjust to it. Spend some time each day thinking about any dreams you had for yourself that you were never able to follow...you may find the seed there of the new life you want to create for yourself. If you had a talent or passion in your youth, look into taking some classes in that area. Distraction offers some relief from the pain, and can help you keep perspective.