That's very measured, realistic and well characterized. I could definitely see this happening in exactly this way. I like the matter-of-factness of the sex ("They’ve done this before; they know what not to do. It makes it a lot better than the last time if memory serves.") and I love their conversation; it's like they don't quite communicate at some level even though on another they really do. I also like your writing style and the line I quoted was just one example of parts that I thought were really elegantly written.