I don't know if my experience is ANYTHING like what you and your wife are in the middle of, burnout.....but I thought I'd offer it up. It might help at least to know that someone else has been there, and got through to the other side.
Communication has to be more than a laundry list of "I wants" and "I needs." It's about how you're both feeling, where you're both at, how your lives are impacting on your desires. It's not just making plans, it's about why those plans don't materialize. AND it's about reassuring the other partner that it's ok if they don't. Because, at least in my case, worrying about not being "on" for the plans was self-defeating.
When I was going through an incredibly stressful period with work and life changes, it was all I could do to get through the day. I had no energy left for sex, and no interest in it. It went on for months. My darling boy got frustrated, and let me know in no uncertain terms that he loved me, he'd never leave me, and he wanted to help me sort out my problem....because he missed our active sex life.
Of all that, the only part my stressed out mind heard was "he wasn't getting what he wanted from sex." Which I translated quickly into "on top of everything else that's wrong with my life, I was a failure in bed." It was a complete misinterpretation, but I was seriously in a bad head place. Anyway, nothing turns a person off faster than the belief that you're doing it wrong...and pretty soon, every little pass was seen as a judgemental demand. Note again, the guy had done nothing wrong....this is just what was going on in my head.
Long after the life stress went away, I still was having these "pressure to perform/failure" reactions. I wanted sex again, but kept shutting down at wierd times. Like, halfway through a blow job...or while he was going down on me. Wierd stuff. It took me ages to explain that I wasn't rejecting him...I was feeling (ironically) rejected and insufficient. Irational, but true. And then loads of time with him accepting graciously what I could do and reassuring me it was good. More would be welcomed, but he was happy as it was.
Long story short (I know, too late)....stress makes some people crazy. Sometimes that crazy turns up in the bedroom, specifically because sex touches us so deeply. It took us 6 months (well 9, if you include the initial stress that started the ball rolling) to get through it. But we did, and we're back to our old form. Nobody had done anything wrong, I couldn't (literally COULDN'T) have helped my reaction. But we had to do a lot of things right and love each other a hell of a lot to get us back on the right track. Most importantly, he made an effort to let me know how good the good parts were. Building my confidence back.
Anyway....like I said, don't know if it's any help. But it's what I have to offer. I'm around if you want to chat (or, good heavens, you introduce her to Pixie's and she wants to chat

). Hope you guys find your road back.