All that came to my mind was something similar to what Havest brought up. Knowing she has this PTSD diagnosis, do you somehow view your wife as damaged now, you dont know what to do with her? Dont know how to treat her? Fear that you may do something wrong that may trigger her, damage her more? That she is somehow too fragile to deal with, that you have to tread too lightly, walk on egg shells so rather than make a mis-step, you take no step at all? Is it all too much to cope with and that is why you cannot process or retain any of the information you discuss?

It sounds to me that individual therapy is what you may need to sort thru what you have written here. There is a definate block keeping you from being able to engage with your wife. It sounds like you really love her and want to make this work and I think a therapist is best qualified to help you sort out these feelings you are describing.