My W has been doing the same for a long time...comes out for a while, then goes dark/dim or "inside" (since we still live together...I think with her at least its part of the ruminate, process, talk, ruminate, process, talk cycle...maybe for yours?
I agree that its a nice break sometimes when they go inside for a while...I hope he is doing some good internal work right now... T^2
In the depths of winter, I finally learned that within me there lay an invincible summer. - Albert Camus
Uncertainty is the very condition which impels people to unfold their powers.-Eric Fromm