relationship dilemma...

[~rachel~]

A close friend of mine had a relationship with a boy who's also a friend of mine. They parted on bad terms a few months ago but now I have become really close to the boy. I think the feelings I have for him are mutual(sp?) but I'm reluctant to takes things further as I really don't want to hurt my friend. Would starting a relationship with him make me a 'bad friend', what are your experiences with these kind of dilemmas- do they work?