Arthur doesn't doubt John's happiness, not one inch. But he doesn't talk about those darker, pettier urges as much, so they deserved some proper weight and respect when he did.

"You know," he hums, rubbing his thumb along the pulse point on John's wrist. "One of the very first stories, the very first chapter, even, in the Bible - it's of two brothers, the sons of Adam and Eve, God's first humans. Both of them offer up the products of their labour - Cain, the elder, he was a farmer, and offered God his wheat - Abel was a shepherd, and offered him a lamb. God chose Abel's offer, and Cain, in a fit of furious jealousy, killed his brother for it."

He rests his head on John's shoulder. "So, really, being mad at your sibling for something is one of the most normal, human things in the world."