Conjure Wife by Fritz Leiber

The rhythmic rattle and surge of the train had a soothing monotony. You could hear the engine puffing lustily. The wide, heat-baked, green fields swinging past the window of the compartment, drowsed in the noonday sun. The farms and cattle and horses dotting them here and there, looked equally somnolent. He would have liked to sleep, but he knew he would not be able to. And as for -- She apparently never slept.

"I want to run over some things," he said. "Interrupt me if you hear anything that sounds wrong or you don't understand."