Remington Steele: NBC television, 1982-1987. After four years of romantic tension between the male and female leads, the producers have the characters get married. The show dies after six more episodes, partly due to failing ratings (and partly, it must be noted, because NBC programming preferred Hunter and scheduled it in Steele's time slot).
Moonlighting: ABC television, 1985-1989. After two and a half years of romantic tension between the male and female leads, the producers (and the characters) yielded to temptation. The show's ratings took an immediate nosedive (aggravated by the stars' lengthy absences, Cybill Shepherd to have a baby, Bruce Willis to make Die Hard) and never recovered.
Catwoman: DC comics, 2011. After seventy-one years of romantic tension (off and on, mostly off through the height of the "seduction of the innocent" scare and the Comics Code) and endless did-they didn't-they hints and parallel-world cheats, Batman and Catwoman have undeniable on-panel sex in the rebooted issue #1.
In a similar vein: If you loved Starfire on Cartoon Network's Teen Titans, you'll hate her in Red Hood and the Outlaws.Shortpacked! by David Willis - Math