"Man Cave" is married-folk slang for "some personal space where I don't mess with your stuff."
Have a gaming rig on a table that your wife can't go near? That's a man cave. How about a car project in the garage? Fishing boat out back? Electronics bench full of parts and tools?
My issue with "man cave" is that it's derogatory. A man has a personal hobby he enjoys, which she doesn't understand, so it's addressed with terminology like, "man cave." Really, do you want you wife referring to you as a neanderthal?
As for trekking in Nepal, it struck me as a tremendously abbreviated comment. Could, "trekking in Nepal," possibly describe the sort of action a man so distraught wants to take?
This is akin to my wife being upset at my emotional distance and refusal to address her needs and, when called on it, I simply say that it's fine if she buys some new shoes.
