Thanks Hamster.

I haven't brought it up with a medical professional just yet. Not sure if I'd ever be able to. I know that it's their job to hear about these kinds of issues and to be professional. I just always have trouble talking about it or even bring it up, and that's with people I know. I prefer to just kind of bury the issue, socially speaking. I haven't even spoken about it with my own parents for many months now. I regret ever telling them about it in the first place, so this suits me just fine.
As for the possibility that I have some kind of absurdly rare medical condition, I'm sure it's possible. But I think it's a very slim chance. I've done a ton, and I mean a ton, of research on my own time into this possibility and have found no medical condition that fits me. I can't help but feel that if I did feel the need to tell a doctor about this, he or she would recommend me straight back to a therapist.

As for this paradoxical approach you talk about, I think I get what you're suggesting but I don't think it's something that could work for me. Could I try it? Sure. But I know from all the times when I have tied to compromise with myself that I will always be saying to myself that I can do better. That I can beat this thing. I'll certainly keep your suggestion in mind though.
I'm actually trying for the exact opposite at the moment. No pornography, no masturbation. It's only been a couple of days, but I feel great. I'm just happier and more optimistic all around when I make a conscious effort to purge all things sexual from my life. I feel like a better person, like I deserve to be happy, does that make sense? I don't know how long it can last, already that horribly familiar nagging feeling is tugging at the back of my mind when ever I have time alone. It's not like I haven't tried this kind of "cold-turkey" method before. I can't say with certainty that I won't start back up again and just wallow in my own self-hatred like I've done so many times before, but I'm going to enjoy my time on top while I can!

I must sound like a broken record at this point, but thanks once again to all the people who have taken the time to read and comment on this thread. I've pretty much given up on therapy at this point, so it's nice to have a place to discuss this.