In fiction, you're on your own. The punctuation is part of the art of it. But those two commas are good in my opinion. The first is necessary, and the second is writer's choice.
An introductory adverb gets a comma by convention. It relieves both the reader and writer from indecision. Such commas are invisible to the experienced reader. The second one changes the grammar slightly. Without the comma, the way they lay in bed was holding each other. With it, they held each other in bed. That distinction is slight, and I might be making it up, but either way, the comma doesn't