Thanks for your reply SPO.
It doesn't sound as though you have got very much information at all about the affair and so much of your obsessing is probably your need to fill in the gaps.
Acknowledging that we are all very different in our "need to know", the reason so many people have this compulsive need to know EVERYTHING (and I was one of them) is because there was a period in your life when you were being deceived. That period feels "unaccounted for", because things were not as they seemed at all.
The general rule in this is also that whatever you need to know, your H should tell you. He cannot be the arbiter of what's good for you in this, either.
It doesn't sound as though you have started any work as a couple on reconstructing the story of your marriage, the story of the affair and your H's personal vulnerability to this happening. The latter issue is crucial, because if your H doesn't do some work examining how or why he became vulnerable to infidelity, it could well happen again.
Shirley Glass says in her book that infidelity is hard enough to get over with therapy - and without it, virtually impossible. I completely agree with that assertion, but I would always advise that the unfaithful party gets some solo therapy first, to unpick what it was about their character, personality, familial and lifestyle vulnerabilities that led to this.
I have this impression of you left hugely in the dark about this seismic event that happened in your life. I fear that this will lead you to have many more darker days, because even if recovery is going well and healing is coming along, most betrayed partners hit a kind of wall a few months on, when the drama and crisis has subsided and all they are left with is the sadness and sense of loss.
Many people in your H's situation hope that things will blow over and things can get back to normal, but please don't pass up this opportunity to get the marriage you feel you deserve.
Read that book, get your H to do so too and if it helps, start writing down a list of questions that are going through your head all the time you are alone and obsessing.
I think you'll find the book really helpful because you will see that so much of what you're feeling is entirely normal, including your fear of meeting the OW.
Will your H get some therapy? Would you also consider some solo counselling so that you can process your feelings? I often advise couples to delay the couples counselling for a while until work has been done with the individuals - and after the dust settles a little. However, it strikes me from what you say that communication is a big issue in your relationship and so I think you would both benefit from some couples counselling at some point.