I kind of have to agree with ArtChic, although you state that you aren't gay/bi, you definitely exhibit some strong characteristics of someone that has homosexual tendencies. Sure your mind says no, but your sexuality has both inborn and choice parts. I truly believe that one is heterosexual, homosexual or bisexual at birth...and then we make conscious decisions on how we act on those parts of our personality.

I know that I'm bisexual because I get erections at just the thought of having sex with a guy or a girl. The erection is instinctive, it happens without me deciding it to happen. I can choose to do something with the erection or not, but the erection was all natural.

You may choose to not want to pursue your friend sexually, but there are natural parts of you that are physically, emotionally and sexually attracted to other men.