I am the type who needs to know a lot. I would prefer to know every detail. At the same time, I have decided that I will need to choose what is actually relevant in healing the R and that's the part I would want to know (e.g. how exactly did the attration start? what is it that you see in her that you don't see in me? why did you do xxx thing?)
Unfortunately for me, H is still in contact with OW, though PA is over and it is currently not much of an EA, more like H feels guilty towards dumping her out cold. But I told him we cannot live like this forever so we are in a limbo now. Back to the subject, I cannot ask the questions yet. Also, H, at least at this point, already said he will not tell me certain things. He is a very private person so I doubt he will ever reveal much. I don't know if this will change later when he is 100% with me and realize that I really need the info to heal, or I will just have to let go.
IMHO, find a balance between what is useful to know (for healing), and what is just, well, details. If you have that list, may be you can hand it to h and have him answer them on his own timeline.