Well, no, I've never et a demonstrandum, but I'll try anything once.
What's it taste like?
Seriously, though, people need to remember that marriage is about more than sex, more than property rights, even more than children. It's about love that gives without taking, gives no matter what goes wrong, love that gives selflessly. It's about training men and women to make the kinds of sacrifices required to join two completely different kinds of people into one. Those two are then prepared to make the sacrifices necessary to keep society going smoothly. They also becomes the model for the children who must learn to do the same thing.
When people started getting out of marriages for no better reason than the sex wasn't good enough, or they had to "find themselves" the model was broken.
Homosexual relationships are for people who can't even make the sacrifices necessary to live with a member of the opposite sex. Anyone can live with a member of the same sex (with or without the sex) as most of us have proven by living with roommates in school.
Marriage, true marriage, "'till death do us part marriage" makes men out of boys and women out of girls. And it is such a universally recognized pillar of civilization that every culture in the history of mankind has included it.
Shalom.