Have you considered having yourself
actually castrated?
No, seriously, have you? Don't dismiss the idea out of hand. If you really want reduced libido, it can be easily granted through elective surgery. Remove the testes and you eliminate sexual urges at the source. It's one of the simplest and safest operations known to medical science.
Ultimately, it's your body, to do with as you please. Just bear in mind that castration is a real option. Even if you don't go through with it, it is a good thing just to have seriously considered it. The mere fact that you've made a decision one way or the other means you are not entirely at the mercy of biology, but have chosen to be the way you are. And that takes some of the sting out of the whole business.