I think there are 2 approaches here that are needed at different times.
Of course you feel that you need answers, but your marriage is in emergency survival mode at the moment. You have to let him feel that he can enter back into this marriage without being under scrutiny and being questioned the whole time. You just need to supress you natural desire to snoop and question.
In the longer term, research seems to show that couples do need to be open about what happened in order to move on. But that's for the future, not now. Always you have to try to keep your eye on the bigger prize.
You cannot teach a man anything; you can only help him discover it in himself. Galileo Galilei
