Answer

Q. How many homosexual people got married in the world?

I couldn’t find the exactly number of homosexual people who get same-sex marriage in the world, so instead, I selected this story about Japanese man got married to American man. According to the article, there were 18000 couples who get same-sex marriage in California.
When California allowed same-sex marriage (March in 2008), Japanese man named Mr. Nakamura could get married to American man in August. Mr. Nakamura is 34-year-old and his sexuality is gay. He has noticed that he is gay since he was a child, so he had thought marriage is nothing to do with his life forever. But after knowing he can get same-sex marriage in California, he had some hope toward marriage. The two held wedding ceremony at a city office. They felt happy to this event, but November in same year, same-sex marriage is prohibited. Now certification of the marriages which were allowed from March to November are stopped for a while.

(伸二, 中井. "同性パートナーシップを考える　＜カリフォルニア州で同性結婚した日本人男性＞." JANJAN NEWS(Japan Alternative News for Justices and NewCultures) (2008): n. pag. Web. 21 Jun 2011. .)