I don't become biased or treat them any different, but I will think of them differently. I will think of them differently from when a boy likes a girl. I love them and I would always treat them as fairly as I did before, because sexuality should never be reason to mistreat a person, but I will think of them differently. If my sisters' sexuality changed, I would view her differently. A person's sexuality will change other's views on that person. Sexuality is part of your relationships with other people. I don't want the Spider-Man I know and love to become too changed. He was white, straight, about 5'10, and kinda skinny.
I wouldn't want to see him changed to fit a different character mold, when everything I liked when I read Stan Lee's run Gerry Conway's, Roger Stern's, etc. The reason why I wouldn't want to see him bi either, is because it goes all the way back to the initial establishment of a character ideal. My opinion is that I wouldn't like him bisexual, either. A person's opinion is all what matters on this board.