I agree with movingupward, I think sometimes the contradictions are lies but just not putting importance on things that we do.
I have a couple theories on the need to know details. First, I think a BS needs details b/c we don't know what is true, details help us get a clear truthful picture of what happened. We need to know the actual event before we can begin to heal from it. Same reason when we find out a friend or family member has died, we ask, why? how? when? we're not being gruesome, we have to make peace with something horrible and we need the truth of the event in order to process it and begin to heal. So the first thing I'd do is sit down in a journal and write out the affair, what happened, why, how, etc. See if there are holes somewhere in there that are causing you this need for details. From experience, if there is a major conflict your mind will not rest until it is resolved and if you can pinpoint where it is you'll be able to get to the bottom of it more quickly.
Secondly, I feel that a BS asks questions b/c they NEED to know why. How could this person that we love and trust do such a horrible thing, who are they? We are digging for clues in their descriptions of who they really are and why they made the choices they did. I think if you decide there are no holes in his story this might be what is driving your need to know details. In my experience, it was not what my H told me that helped me understand it was more about understanding what was going on with him prior to the A and changing my perspective a bit, putting myself in his shoes. When I did that I had a better understanding. I can say 100% an A would never have been my choice had I been in his shoes, he was sad, frustrated, etc, something we all have been from time to time, I have been, especially after d-day I was SAD, as you know. and after d-day I wanted comfort, I wanted to be happy, I wanted to be treated kindly and sometimes I wanted to escape for a bit. I drank more, I smoked more, I shopped more after d-day and suddenly I saw that an A would have those same "benefits" an A is a way to escape from real life, having someone tell you your hot is nice when you feel like shit.
That is how I understood, and once I understood I didn't need my H to explain it anymore, I got it.
There are probably more reasons, I'm not a scientist, that was just my experience.
I think it's not about putting it aside in order to move on but making peace with what happened. Not accepting it but understanding why it happened and knowing how to handle those feelings in the future in a more productive way. Knowing that my H and I talk more honestly now, that we share when we are scared or worried instead of keeping it in helps me move forward in our marriage.