This was in response to MaxLam, but I didn't realise that there would be so many replies in between. Ah well.
Who's defining what's civilised and what isn't?
You just completely made up your own definition of sexual civilisation with absolutely no justification whatsoever (and all the other definitions of what's permitted/acceptable).
More to the point, "Rules regarding sexuality" vs "Free sex" are two completely arbitrary definitions, not to mention the fact that they are two unrelated things. Sexuality and sex are like apples and oranges. More to the point, and I really don't understand how people keep missing this: nothing has changed about sex/sexuality. What people are actually campaigning for is for a more accepting society. I.e. get your nose the fuck out of other peoples' business. They don't want you interfering with what they do, and you don't want them interfering in your furry hentai fantasies or whatever perverted shit you're into. Live and let live! People tie each other up to turn themselves on, hell, people shit and piss on each other. Honestly, it doesn't affect me in the slightest, so why on earth should I give a shit (if you'll pardon the pun). People who shit on each other have just as much right to get married as anyone else, so why shouldn't two guys or two girls?
Gay people had sex in the past, and they will continue to do so. Nothing you can do will stop that. Whether or not they can get married as opposed to a civil partnership affects only their legal rights. If people love each other and live together, they should get the same civil protection, regardless of their gender, orientation, race, age or any other factor. Humans are humans. End of discussion.