Keep masturbating.
It can take many years, but it will eventually confuse your nervous system. Suddenly--in one day--it will turn inside out. You'll start having disgusting gay dreams and feel attracted to any and all men. It's really quite disturbing, but it can be turned off. It will require mental focus, and you'll have to give up masturbation, completely.
Yes, I know. You've never heard anything like this before, so you're sure it's wrong. I told you what to do. Either do it, or don't.