You cant. No really, you can't. You can try based of the way they dress and talk and act but that is stereotyping someone. If a guy is gay, and comfortable with it, then he probably wouldn't have a problem telling you or anyone else, if he is not, then leave it alone. The only thing being gay means is that you are attracted to the same sex. That is it. Nothing else just comes with it. In my opinion its only appropriate to ask if you are good friends. If he says no, then either he isn't gay or doesnt wanna talk about it.
there is no possible way to prove anyone is "gay" without asking. Now someone can tell you that this person had sexual relations with them, but that doesnt necessarily mean they are gay
You can't. The only way to know is for him to tell you.
How about trying to hook up with another gay, then both of you get what you want.
you can by asking him
Asking him is the ONLY way to tell. Or better yet, you can focus on your own life instead.
You can not really tell if someone is gay, you are better just asking the person if you want to know.
by asking :)
You can tell that some guy is gay by asking him his best friends, and by observing his behavior about other men.
You can't. The only way you will figure it out is by asking.
It would be best to indicate in conversation that you have other gay friends and that you do not have a problem with gay people. Perhaps open that door with a political conversation i.e.: California's recent Prop.8 controversy. If you have a problem with people being gay then you really don't need to know if someone is gay.
Your question doesn't really make any sense...are you asking if he is gay? Or are you asking if he will have sex with a guy? or what? I believe he's bi (not factual, juss myopinion and wishes because i'm gay) If you are asking if he will have sex another boy then the answer can't be answered until he comes with his sexuality which he has not. If he is bisexual then he someday maybe me ;)
He Is gay and is cheating on you with the masseuse.