It's night time, Robert Jordan's outside in his sleeping bag, and you know what that means.
He's waiting for Maria.
Earlier that evening, he had cut down a small tree, cut it up, and used the branches and trunk to fashion a makeshift bed.
Pilar had promised him she would watch the sacks with the explosive during the night.
Robert Jordan said goodnight to everyone, and went back outside. Nobody can seem to figure out why he would want to sleep outside in the snow.
Anyway, out here on the forest floor, Robert Jordan smells the odor of pine boughs. There's a smell he loves, not any of that gross death stuff. He also likes the smell of bacon, coffee, and cider mills.
Somebody makes a sound, as if to come out of the cave, but then whoever it is ducks back in.
Robert Jordan is getting impatient. When is that Maria coming?
Maria comes. Wearing only her "wedding shirt." She gets into the sleeping bag.
They kiss. Off comes the wedding shirt.
Maria says that they are one – one body, one heart. Hasn't he felt this too?
Yes, he has felt this too.
Yet, says the unusually perceptive Maria, they are also different! Who knew? But she wishes they were exactly the same.
Robert Jordan says she doesn't mean that.
Maria means that. She would like to be him, because she loves him so much.
Then presumably they get it on. Or at least that's what we assume from the shift in their dialogue: "Maria." "Yes." "Maria." "Yes." "Maria." "Yes." "Maria." "Oh, yes. Please."
"Afterwards," they lie together, and decide that what just happened wasn't quite so amazing as the afternoon's sex in the heathers. But Maria liked it more.
They fall asleep. But Robert Jordan wakes up later in the night, and lies there in the sleeping bag thinking.