I can't believe people still get married and limit themselves to one female. It's not even a female you seem to love, and you can't tell her jackshit about who you really are. You've got some fucked up priorities you need to straighten out first before you question a fetish community that's existed in the pre-internet days mind you, guro didn't start with pixiv and GC. Younger people being fed this puritan crap, seem to believe now that fetishes are nothing short of being "sick perversion!" and "brainwash from the porn industry", but that's completely wrong. I've been seeing that talking point a lot lately, but the unbiased answer to what fetishes are, are attractions to weird shit you can't control that you've been attracted to since pre-puberty. The reason your girl doesn't understand is because women in general have sex drives immensely lower than men, and they tend to hate "icky" stuff, which prevents them from developing strange paraphilias when they're younger.
In short, you will never be happy if you're tied down to a person that doesn't even get you. You're literally just a sex machine to her, and she can find someone better, "less weird" as you'd say.