Yes--Dan Savage has been memorably eloquent on this topic.

Although Felix is definitely a 6 on the Kinsey Scale (http://en.wikipedia.org/wiki/Kinsey_scale), there's also something personal there, some bugbear that I can't get a lock on. It's a mystery, like what Gideon's hold on Thaddeus was and what, exactly, Mildmay did to Griselda Kilkenny.

My characters have secrets. Even from me.