Flynn asked, and I guess he just got his answer: the lack of marriage in Lord of the Rings Online isn't down to any fears or prejudices against same-sex marriage amongst the developers. It was done to keep the whole thing canonical. The issue that broke the marriage option as far as the developers were concerned wasn't same-sex marriage, it was inter-species marriage, which is mentioned only sporadically in Tolkien's work and only ever concerns unions between men and elves. Rather than mess around with men marrying dwarves and rangers bedding down with hobbits, they decided to scrap the whole kit and kaboodle. Which was probably for the best. You upset Tolkien fans by messing with LotR canon, you're liable to end up hurt.
The Great Lord of The Rings Online Gay Marriage Debacle [GayGamer]