For me it's a big NO.. bcoz tis kind of incident juz happened on me.. both of them hv developed "feeling" to each other..

mayb guy n girl can only b good friend when both of them r stil single n available.. if either one is attached, then no way..

what?? married and available???

anyway, if u r attached n u know well ur limitation then of coz u can hv a opposite sex as a good fren.. n so do ur good fren is.. n make sure ur partner is well-known of ur friendship n no hidden things n dun do anything tat can make ur partner feel suspicious..