How do i get rid of a Gay fetish

I've (M) never been attracted to men, not in the slightest. I've even gotten screwed by a man, and it was so horrific that I never want it to happen again. but due to a deep rooted childhood fetish stemming from unrestricted internet access, every time I watch porn of that nature i get involuntarily hard. (Note; i did this to see if it would work, not to get relief to) And when i watch porn of women, i have to struggle to get anything. i have no idea how to stop this from happening. i can't get hard for women, despite my massive attraction to stuff like boobs and ass. do i need to keep trying or something? i know that later in life this is going to effect me greatly, and if i can't get a hold of it now, what are the chances i get ahold of it in the future? Plus, my gf is a hard Christian, she discovers that i can only get hard to men and it's over. please help, I hate this so much.

Edit; What i mean when i said screwed by a man i meant i was forced to be screwed by that man. he's in jail now for that crime, and i fear ever being alone with any man.