A young couple is snogging. The young lad asks, "Can I have a blowjob, please?"
"No way!" replies his girlfriend. "Why not?" he asks. She tells him, "You won't respect me afterwards."
Three years later, they get engaged. After a celebratory meal at a posh restaurant, they go back home, and he asks, "Can I have a blowjob, please, love?" "No," she replies. "You won't respect me afterwards."
Another three years later, they get married. Lying in bed together on their wedding night, he asks again, "Can I have a blowjob, please, love?" "No," she replies, "You won't respect me afterwards."
Twenty-five years later, they are sitting in bed together. He puts his book on the bedside cabinet, turns to his wife of 25 years, and asks, "Can I have a blowjob, please, love?" "No," she replies. "You won't respect me afterwards." He yells back at her, "Look! I've known you for over thirty years! We've been married twenty-five years! We've got two kids, one grandson, with another on the way. Surely, by now, you must realise just how much respect I have for you!" "Oh, OK, then," she says. "I'll give you a blowjob." —and she does.
Ten minutes after she finishes, the phone rings. The husband turns to his wife and says, "Well, answer it then, you fucking cocksucker."
Explanation: For decades, the wife refuses oral sex because she claims he "won’t respect her afterwards." Finally, after 30+ years together, she agrees, implying that respect is now unquestionable. But right after, the husband calls her a "cocksucker" in an insulting way—proving her original point that he would disrespect her afterward.