Every woman wants to know what's going on inside a man's mind. The reason isn't simply that they are curious but because of something that has happened in the past.
I'm sure you can remember a relationship that ended badly. Everything seemed to be going fine until you heard the words that made your heart sink, "We need to talk."
Then the end came and you never saw it coming. It is the greatest fear that anyone can experience...being blindsided by something that was totally unexpected. So if you're a woman, I can understand why you want to know what's going on inside his head.
Is he upset?
Is he thinking about leaving?
Is he bored?
Here's a good guide for you
Don't just look at the current circumstances, but focus on the previous few weeks. Have you two been fighting and just can't agree on something? Is he upset that you don't listen to him or does he feel that you won't even consider his opinion, because if that's the case then he's being quiet as a result of feeling disrespected.
The good news is that most of the time, a man is quiet because it is relaxing. He doesn't have dozens of feelings and thoughts racing through his head at any given moment (like you do). In his mind he's either extremely focused or his mind is in park.
Here's your take away
If you have been fighting and he's acting quiet, then you need to work it out. Don't let resentment build. Most of the time, he's simply....being a guy.