I don't know your wife so only you can truly answer this question. Is it possible that she has been so traumatized by guilt over her affair that she has repressed the details? Is she in IC and/or are you both in MC? Can this be explored there? Have you thought about a polygraph test? I really don't trust them but maybe the threat of one will jog her memory. I can understand you needed to know the details and to hear it from her but you should make sure she is actually able to provide them before you hinge your R on them.