Oi Vy!
FIrst of all, please dont call yourself sick! You are not Sick BH. You have desires and fantasies and dreams and what not. That doesnt make you sick. 

Ill tell you a secret, it very highly possible that you are not even so attracted to that guy, ive seen lots of times when we try to fight the desire because it makes us feel sick and we keep fighting it, then the thought will persevere, and eventually it will find a way in. Ive seen this over and over. 

its the same with regular SA. Sometimes you can see a women and my first response is oh god am i attracted to her? And i will try to find a reason to not be attracted but my mind will then find something that does attract me. The best trick is to tell yourself "Maybe that person is attractive, maybe not. I will never find out not do i realy want to. Yes, there is a part of me that wants to feel that pleasure and thats ok, but i dont need to go and follow that thought all the way to hell.....

Its the same way someone with a eating addiction would think when seeing a delicious dessert. Yes, it looks great, i know how it feels, but i dont need to go there. I can move on with my life. 

Its just our brains are stuck in this mode of seeking that pleasure. We just need to train the brain different ways of thinking.

Love