Human Is is a 1955 Philip K. Dick sci-fi short story where a guy goes to another planet for work and when he comes back to Earth his personality has flipped from an asshole to a sweet, kind, considerate man. Everyone's immediately convinced that an alien has taken over his body, this goes all the way to court, and in court his wife testifies that she's noticed no changes at all and so the charges are dropped.
And then there's a bit right at the end of the story as the wife and the husband are walking out of court:
Jill turned abruptly. "What is your name? Your real name."
The man's gray eyes flickered. He smiled a little, kind, gentle smile. "I'm afraid you would not be able to pronounce it. The sounds cannot be formed..."
Jill was silent as they walked along, deep in thought. The city lights were coming on all around them. Bright yellow spots in the gloom. "What are you thinking?" the man asked.
"I was thinking perhaps I will still call you Lester," Jill said. "If you don't mind."
"I don't mind," the man said. He put his arm around her, drawing her close to him. He gazed down tenderly as they walked through the thickening darkness, between the yellow candles of light that marked the way. "Anything you wish. Whatever will make you happy."
And I. God. There's something there. A soupcon of monsterfuckery. To tell your partner in a moment of intimacy that yes, you're something so inhuman that the lips you're stealing can't speak your actual name. You're a parasite that not only had the ability to burrow under this man's skin and take over his life, but you were so desperate to escape a dead, dry, blasted planet that you did.
And for your partner to then turn around and go "I know, I've always known, and I love you" is just. God I know it's not a great Dick story but something about it is making me lose my mind
