I saw a similar question asked on fetlife once.

I'm out, but I only told my wife. It was very, very difficult to do so, but I felt it was important so I did it. I had so much adrenalin running through me my wife thought I was going to need a doctor.

As for our relationship, she took it extremely well. To prove to me that she was cool with it she found a heavy blade and submitted for a beheading the next night. She's way, WAY cooler with my snuff kink than any of my other fetishes and we've roleplayed many times since I told her.

Her thoughts are, from her point of view, no matter what I choose it's fine. If I don't snuff her we just go about our lives after enjoying our night. If I do kill her it's still fine because she won't be aware of being dead, or having ever existed, or anything. From her point of view it's consequence free either way, so why not enjoy a kink that matches up in many ways with her submissive kinks?

Neither of us has told anyone else though. There's not really a need for the most part, but we might also lose quite a few friends if we did.