What are the taboos and misconceptions that still surround sexuality and why?

There's the fundamental problem of the myth of monogamy that's compounded by the screwed up sexual ethics and teachings of the christian church. 1 man 1 women, he's always a dom and she's always pregnant. Noone would say everyone has to eat only 1 type of meal or drive exactly the same car or same clothes. why accept that for sex?