Our spare bed

 "Jeremy is asleep, so I thought I would come and see if you are comfortable in our spare bed"

"This is your 'spare' bed? It's a King Size Simba, one of the best in the world. And this looks like yours and Jeremy's bedroom. This ain't no 'spare bedroom'. Is it!"

"Oh you rat! You've guessed! My hubby is old fashioned and believes that all guests should be treated to the best he has to offer."

"That's very commendable, letting me experience the comfort of his own marriage bed." 

"Not just our bed either."

"Then, for whatever else is on offer, ...

 ... please tell Jeremy, I am deeply grateful."