Dan Savage really is kind of awesome, and hits on what I personally believe. It's more important to be emotionally giving and generous to your partner than it is to be in bed with one person for the rest of your life (consent of partner given, of course). Sometimes I wonder if it's just being culturally gay that does it, but there's a lot to be said for the lessons learned from gay culture being applied to straight relationships as an alternate model. It seems hard to me to call Dan's act immoral.
"In “The Commitment,” Savage’s book about his and Miller’s decision to marry, he describes how a college student approached him after a campus talk and said, as Savage tells it, that “he got off on having birthday cakes smashed in his face.” But no one had ever obliged him. “My heart broke when he told me that the one and only time he told a girlfriend about his fetish, she promptly dumped him. Since then he had been too afraid to tell anyone else.” Savage took the young man up to his hotel room and smashed a cake in his face."