If this is something you'd truly like to work on, not out of a sense of guilt but because you would enjoy occasionally reciprocating, there are a wealth of resources out there for the enthusiastic amateur (you are far from the only would-be blow-jobber whose spirit is willing but gag reflex is weak). You have more options than "no blow jobs, ever" and "regular whole-hog sessions to completion that result in vomiting."

You're right to want to minimize your compulsive physical behavior in the workplace before it bothers your co-workers, but I hope very much you can also give yourself credit for the work you're already doing.

I hate to get gender essentialist, but I'm starting to think that a lot of married men have some sort of heterosexually induced dentistry aversion.

Not wanting to give everyone in your life one of your kidneys is not the same thing as hoping they die of kidney failure.

As you feel increasingly comfortable around your friends, I think it's more than fine to share the basic details of your heroin addiction with them. If they seem receptive, you can feel free to talk about it in further detail; if they seem judgmental or uncomfortable, you can move on to other topics.

Someone who responds to "Please don't grope me" with whining and pouting isn't a friend. He's an asshole and a predator.

Addicts sometimes have a penchant for becoming the center of attention at other people's celebrations.