A sex counselor could probably help you sort through all of your feelings. You're not some sick and twisted person, but you certainly sound confused by your fantasies.

The real problem with zoophilia lies in consent. Even though the Basset hound down the street grabbed your leg and went to town, he can't actually give consent. Much like someone who is heavily intoxicated. In any sexual relationship, consent is extremely important and animals just don't have the intelligence or communication skills to be able to give that consent.