Perhaps as a lifelong nerd, I have an uncommon perspective on gay marriage. I've always been on the fringe. When I was in high school, being into science fiction, fantasy, and comic books was a sure fire way to be on the outskirts of the "cool" group. When I went to college, I didn't hide who I was, but there were enough other people who felt the same way that I didn't feel anywhere near as alone as I did is high school. Now my predilections are mainstream, and those of my kids who follow the same path don't have nearly the same obstacles to acceptance that i had.
In some (not all) ways, being gay is the same. It's achieved a modicum of acceptance thanks to the internet and the ability for like-minded people to connect, but it still hasn't reached the goal of mainstream acceptance.
It'll get there.
And one of the reasons is because there are many of us who in some SMALL way understand their plight and don't want others to have to go through what we did in ANY way.