I went through a weird and complicated sexual evolution but basically before yiff I thought I was straight, then when I was like 17 I found yiff and for a couple years and was bi for furries and pretty much ace for humans. Eventually I came around to liking people a bit again and I've been openly bi for the past five years or so.

I don't think I ever was not bi, and in retrospect I can recognize I had some gay feelings when I was younger, but yiff helped me realize it. As for why I pretty much only liked furries for a while, I think there's just some sort of idealized aesthetic appeal they had that real, imperfect, people didn't have. But once yiff became the new normal for me and not something so exceptionally different, I began to appreciate humans again. I still heavily prefer furries though.