I'm a pretty calm and reasonable guy most of the time. My adrenaline does kick in when someone insults me and I do have to struggle to maintain my composure, but so long as it's me that's being insulted and not a loved one I can keep my cool.
However, I know that if something did happen to a person I loved I would turn into an absolute monster. It's more than beating up a guy or killing him. I mean ****ing Jeffrey Dahmer shit. I mean targeting his loved ones and saving him for last. Crazy shit like that.
There are few people on this Earth that I love. Let's hope nobody messes with them. Any shred of humanity or morality would go right out the window.
In my case I really don't care if I snap. For the most part whoever's on the receiving end will be deserving. In your case I think you need to first realize that you're not alone. Everyone has demons. Everyone has sick kinks they don't want known. They may not exactly be acceptable, but you don't need to feel like one freak in a sea of normalcy.