Is it normal that i fantasize about my step-mom that i hate?

ok my step mom is kinda hot. But she is married to my dad, but my dads in prison. For a little while i have been fantasizing about her. I hate my step-mom with all my soul. she is a total bitch. i would love to punch her in the face. (and i dont hit women) I have been having some really amazing sex dreams about her. so is it normal that i want to fuck my dads wife that i really hate?