How do people find out their sexuality?

I mean how do people know, Personally i haven't had crushes in awhile now, even in the past i've always like them for their faces, men or women alike. Now I just find it kinda weird. I like reading romance in fiction as long as it's enjoyable, but when I imagine myself having a partner i just find it kinda weird. Even when I see my friends with their partners, I just can't comprehend the idea of me like that. That said, I do find people looking good, but not so much in a "romantic" way but more of an platonic way?