First of all, I will like to say that this will be a very confusing situation to deal with if it happens with somebody. It happened with me and I was totally surprised to know this but then I was not able to verify it first hand since, it is so embarrassing to ask somebody directly and just in case find out that he is not the type of person you actually thought he is. I was living with my other roommates also and we were quite sure about this guy but then none of us had the courage to go and ask him if he is gay.
Then one day some of the girls in our building came to know about it and it became quite famous that we have a gay in our apartment. It is surely not such a big issue but it puts you into an odd situation if you don't know how to confirm it. Finally we quite accepted the fact that it is better not to go any further since it may be very offensive to intrude in somebody else's privacy. Now the guy is happy with other ones and we don't want to know any more.
But, I have an advice to other people who think that there roommate can be a gay. Its not a shameful thing but it may be embarrassing in front of other people are still traditional and consider it against the society. Also, if you want to ask him directly, go ahead do it, it may make you comfortable sometimes. In my case I chose not to because I figured out that the nature of a person should be more of a sign of his behavior than his acts.
