TIFU by admitting to my girlfriend that I pretend she is a giant cockroach when we have sex.

Ever since I was a teenager I have had very intense fantasies about having sex with a giant roach.

It started in 9th or 10th grade when we read The Metamorphisis by Franz Kafka. As I started to think more and more about the roach creature that the character had become, I started to imagine what it would be like if a woman turned into the roach instead. I found this idea very arousing. I would not be repulsed or frightened of her, as the characters in the story are. I would take care of her. Then my thoughts started to get sexual with the character.

Eventually I sort of dropped the bit about her having been a human woman first, and I kind of imagined this fictionalized roach species. They are giant roaches, the size of a person, and have complete intelligence. I kind of over time conjured up an "imaginary friend" of sorts. She was one of these roaches and her name was Ogtha. I would fantasize about her often. Whenever I masturbated I'd be imagining elaborate scenarios of me and Ogtha making love.

When I started to have actual sex, I found I could not, uh...perform, if I wasn't thinking of Ogtha. So basically now, anytime I have sex with a woman, I am pretending that she is actually Ogtha. Not just think about Ogtha, I concentrate intently to visualize that I actually am doing Ogtha. I don't want to think about the girl at all. There is only Ogtha.

Of course this sex can never be as exciting as my fully imaginary sessions with Ogtha, there are things that her multiple appendages and antennae allow for that a human woman can never match.

So anyways, I've been in a relationship with my girlfriend for about a year. 3 or 4 times I have tried to have sex with her and not pretend she is Ogtha, but I just can't do it. So essentially every time we have sex I am imagining she is Ogtha.

I finally confided this to her the other day, and I was blown away by her reaction. I thought she might take it a bit badly at first but that she'd get used to it. No. I have never seen such a look of disgust before. Outraged is not an understatement. She is not even returning my texts now.

I am afraid she is actually going to break up with me and also that is going to tell people about Ogtha. I don't know how I will face anyone. This is going to sound silly but I also feel guilty about feeling shame, as if Ogtha will be saddened by this, even though I "know" she is imaginary. I just don't know what to do at this point.