I understand how you are feeling. I think many of us on SI wish we had handled those initial first interactions with our WP differently. In the beginning I was (not proud of this) really only concerned with making sure we stayed together! I believed what he told me about he A (to an extent) and it wasn't until a couple months went by that the initial shock wore off and anger set it. Then I started demanding the real answers, as I knew that what he had told me already could not have been EVERYTHING.
I think not knowing all the details (or feeling like you don't) is FAR worse than actually hearing the awful truth. If you can't see the whole picture, your imagination is left to fill in holes. Which could be better or worse than what actually happened.
Many times the WP will TT because they are protecting themselves (how selfish!). My WBF told me that he TT because he knew that I would leave him if I knew the whole truth.
If you need those answers to move on, then do what you have to do. Just be prepared that he might not be willing to provide those answers, and if he isn't, you need to be prepared to make a decision for your future based on that.
Have him take a polygraph if that's what you need! If he really wants you to "get over it" then he should be willing to do whatever it takes to help you heal! Even if that means he's uncomfortable!
For him to say that you guys can't move on because you keep asking him about it is just stupid. My WBF used to say the same stuff. Well guess what? You can't move on, because you don't have the truth. He was there! He lived it! He has alllllll the answers up there in his head. That's why its so easy for him to just "forget about it" and move on. And when is your DDAY anyways? They say it takes 2-5 years for a couple to recover from infidelity, and that's IF both partners are giving is 110%, and doing anything necessary. If one partner is unwilling to work at is (especially the wayward in my opinion) then its going to be an uphill battle. Well...it's already an uphill battle! So I don't even know what you would call it then!
I'm sure others will come on with better advice than I've given. I hope you find some inspiration! I know (because I've been where you are) that not knowing everything is just devastating and it will literally fuck with your mind until you go insane. Do something about it, before its too late!
Always know if the juice is worth the squeeze...
ME: 36
1 doggie
DDay: June 24th, 2013
DDay 2 : August 22nd,2017
Left him August 26th, 2017