Is there something wrong with my sexuality?

First of all, I'm 19, male and bisexual. However, I don't get turned on by seeing naked people of either gender to the same magnitude as any friend of mine might when they see a picture of a naked girl. There's always at least one person in my group of friends who would comment or let out a strange sound when there is a provocative picture of a woman. I'm more turned on by men but I don't drool over anyone naked whether in pictures or in reality. Sometimes, I can go a week without masturbating and when I do, I always think about someone specific rather than looking at porn or magazines. Is there something wrong with my sexuality? Shouldn't I get turned on when someone good looking passes by? Isn't it unsafe, psychologically speaking, if I only get turned on by one person whomever my crush happens to be? It's like putting all your eggs in one basket.