Whatever will be will be...
I usually like to get the creative apple juices going on challenges I enter, but not so on this one. I will be direct and to the point.
"Can you be friends with a person of the opposite sex whom you're attracted to?"
I say a hard NO! Or should I ask, what do you mean by attracted?
I say if the person of the opposite sex makes you applesaucy and you are already in a relationship, walk away, to a avoid the temptation, if monogamy is something you value.
If the person of the opposite sex makes you all applesaucy and they are as dry as a bale of hay for you, who are you kidding. You know you are keeping them in your life hoping they will have an epiphany and volte-face.
If the person of the opposite sex makes you all applesaucy and you conjure the same response in them, I say carry on with the friendship and que sera sera.