My advice would be to lean in to what she wants, agree to separate, and work productively with her on the plan with the presentation that you're on board and plan to enjoy this change also. That's going to make her wonder. You want her to wonder what you're thinking, and from this point forward you shouldn't tell her anything about your frame of mind -- nothing at all.
Hey LH19, I found this quote from you in one of Ready2Change's greatest hits threads. Do you remember if this scenario involved the W moving out? Trying to stick to my two main points, which are "I ain't moving out and I ain't nesting" but man, things feel like they have the potential to suck @ss around here if W's mood keeps deteriorating.