The fantasy/fetish your calling into question seems to overlap with your identity problems and coming out as gay. So basically that feel good answer that people are going to give you. Is "Be true to yourself".

But the most immediate answer that i think you need. Since you've described this as a fetish. And you didn't mention your masturbation habits. Is to remove the fetish from your life. Remove it from your porn files and anything else. And then replace it with things you know you want. And actively masterbate to that. Actively reject something you know you absolutely do not want. And eventually the thoughts that distract you in life will disappear.

Just to give you an example. Personally i've found stuff on the internet that gives me a boner right? But the situation itself i find morally objectionable and i personally am mentally disgusted by it. So theres qualities to something that will turn me on. But since i'm so set on being against it personally that i reject it and move on. This is absolutely something you can train yourself to do.

Once you do that. Any moment you ever get where you remember it again and get a tinge of hot turn on/disgust. You will be able to say to yourself "these thoughts can't hurt me". THAT is how you will get rid of a fetish.

EXTRA: I reread my post. I'm a straight guy and I put things blunty at times. But I think i said some helpful things. But I also read some other responses to this post and want to respond to that. You don't need therapy because your gay. You don't need to join any self help groups. This fetish is all in your mind. Its cheesy to say but you need to be true to yourself. Actively masturbate to what is true to yourself. And get rid of what isn't. Your thoughts WILL improve.

.....why is this the first post i decided to post in browseing this forum(no offense. I took an interest in your story and thought i had the answer. good luck)........