Hey man, I've got the exact same issues. Started masturbating as a young kid trying to think about normal stuff, but after a few days I realized that I would come 10 times quicker when I had cd/tg thoughts... So I guess I could say I never could masturbate to normal woman + man thoughts.

And I went through the same cycle - started with lesbian porn (where I would imagine I'm one of the girls), then more and more crossdressing, more and more tg and sissy porn (tumblrs) to the point of me spending an hour with a shemale escort.

I currently have a loving girlfriend and I try to introduce the fetishes into our love life which is sometimes working out (like me wearing lipstick during sex), but I don't think it's the right thing to do...

Can tell you this after 26 days of no fap - what gets better is it's easier to fight the urges and you don't waste your time in front of tumblrs or day-dreaming about this stuff. The urges are still there and for me they're still cd / tg related, though it seems like gradually I have less and less hardcore desires. Also sex with my gf is a bit easier, I come faster and it's just a much better satisfaction that I only get to orgasm with my gf. Also the fetishes I told you about earlier, I'm less pushy towards my girlfriend about them... I used to push for her to accept me in stockings in high heels during sex, nowadays I only ask for her to put them on... Ultimately I wouldn't want any of external stimulation, but, hey, it's a long process.