ok looking at all the rubbish replies so far, i guess one can
see the sort of mentality and maturity singaporeans have when
coming to dealing with such issues.
1stly, assuming u're male, IF you are not gay, then tell him so,
and that as much as u respect his sexuality, he has to show u the
same respect in return. so if u are straight, he should respect
that and learn to control his feelings. besides, point out to him
that this will jepordize a best-friendship that both you and him
treasure. If u doesn't treasure the friendship and respect you
enough to contorl himself, sad as it is, it might be the end of the
road for this friendship.
If u're gay, well, even if u're gay, u have the right to choose who
u want. so if u're gay, its entirely up to you.