In the latest of a long series of Jewish attacks on Western morality, Jewish feminist Hanna Mosin has written an article for Slate advocating for “monagamish” relationships. This, as you would expect, refers to married couples who occasionally – or frequently – engage in extra-marital sex. Her article is interesting, though, for it concedes something that traditional marriage advocates have long known: homosexual couples are rarely monogamous. She writes: The dirty little secret about gay marriage: Most gay couples are not monogamous. We have come to accept lately, partly thanks to Liza Mundy’s excellent recent cover story in the Atlantic and partly because we desperately need something to make the drooping institution of heterosexual marriage seem vibrant again, that gay marriage has something…