During a holiday in bed one never thinks, of course, of analyzing his actions. If you had done so in this instance, you would have seen that you pretended sleep because you had got to an exciting passage. You love your wife, but, wife or no wife, you must see how the passage ends.
Possibly the little scene plays differently, as thus—
"John, are you feeling any easier now?"
No answer.
"Are you asleep?"
No answer.
"What a pity! I don't want to waken him, and yet the fowl will be spoilt."
"Is that you back, Marion?"
"Yes, dear; I thought you were asleep."
"No, only thinking."