I'm so sorry for your loss. My dear father passed away a few months before my H BD me with his A and it was devastating! I had a lot of additional anger that my M problems distracted me from a more natural grieving process. Please take the time you need to grieve his death, practice self care, and try and have extreme patience with yourself and this process.
When my H returned and we started piecing, my anxiety was still high and I felt a need to figure things out and know which direction we were heading. A lot of that was fear. The reality is that we have all the time in the world and the sitch will unfold over time as it should. If you feel that he is avoiding issues, then you can think about what you want to know, communicate that, but also be prepared that your emotional response may he different than you thought. I agree that he needs to be open and share details with you, because you have to learn to trust him again. Just know those details will sting. Also if he refuses to open up, know that you cannot force it. You can however create boundaries and let him know you are not comfortable with his answer, take a step back, and revalue your position. Accepting him back into the M is no gaurntee that the M will last forever, it is your gesture of trying to forgive and mend things IMO.
The hard thing about piecing is that there is no rule book. So we have to figure out how, with constant triggers throwing us off balance. Can you find a M therapist that is pro M and specializes in As? Someone that understands the traumas this causes the betrayed S. There are also lots of good books that help after an A that you can both read. Maybe read them at the same rate and set aside a couple times each week to discuss? Often the Wayward S struggles to see how deeply they have wounded the betrayed S.
Take care. And keep taking lots of time for you and your own healing, with and without H.
Blu
“Forgiveness liberates the soul. It removes fear. That is why it is such a powerful weapon.” – Nelson Mandela