Same here. Share with a friend. Love the idea that she's unaware that he's seen her naked and probably picturing her that way in his head.

I have shared with a couple of my good friends. Another friend has taken pics of our wives an I have most of them but not all of them. It's all good!

Go one step further
 

I have a bikini cleavage pic on my phone and use it as my screensaver. When I goto public places I make sure other guys can see it. One time at the movies I had it on and the guy next to me caught a glimpse and then I saw him lean forward to check out my wife. Big turn on.

My wife and I went to Gunnison Beach at Sandy Hook (nude beach) this weekend. I caught a guy snapping pix of her with his cell phone as we walked back to our chairs from the water.

My wife wears low cut tank tops and I noticed during my daughters birthday that one of my friends was taking pics of my wife's down shirt while she was playing with the kids. It was a real turn on to see it. I never confronted my friend about it. It's a turn on to think he has pics of her tits unaware.

Pics emailed to friends
 

Our group of friends are very prude, no topless and no nudity for the wives, upskirts are rare and may be considered a “main event”. I have only seen one topless picture of an ex-girlfriend of one of my friends.
That’s why the following episode is meaningful, at least for me.
I bought an underwater camera for holidays and I took several shots into the sea (fishes, corals etc.) and a few overwater pictures on the beach with my wife Pam in bikini. Back in the hotel room I found Pam in underwear, bra and panties and I took a picture while she was unaware.
Then I setup the following plan.
I selected two of my closest friends, shy guys with interests in technology and photography and I sent (separately) via email to these guys a selection of pictures (a few underwater, Pam in bikini on the beach and Pam in underwear in the room). “These are underwater, outdoor and indoor pictures of my new underwater camera, what do you think?”.
Then the day after I sent another email to them “I made a mistake, Pam has seen her picture in underwear and she asked to delete it, she is not aware that I sent you the picture, for me it is not a problem because we are friends and underwear is the same of bikini but please delete that photo and do not tell her that I sent it to you”.
The two guys have the photo of Pam in underwear in their PC, I assume they did not delete it and they can use it out of my control (it is a thrill for me!!). After a few years Pam is still unaware of it and as far as I know nobody else knows that the two guys have that picture.

I have a busty bikini pic on my phone of my wife. When she calls it pops up. I've had a few friends definitely see the pic when we've been at the bar and she calls. They were stunned by how small her bikini was.

So have you discussed the photo with them ever? Their thoughts on it? Any thoughts on you doing something similar again in the future?

A few clarifications after the quoted post.
I sent the pictures via email only requesting “technical” comments on the quality of the pictures and of the camera. I pretended to ignore the fact that one of the pictures contained my wife in underwear.
The next day I sent a second email asking to delete the “sexy picture” because my wife could be embarrassed or disturbed, minimizing the problem and saying it was not an issue on my side (actually it was!).
I did not receive comments on the sexy picture but only vague technical comments on the complete photo set “nice pictures, good camera”.
I selected shy guys assuming their discretion and confidentiality, hoping they will not disclose the photo.
I do not know what the two guys did with the photo. As far as I know they did not circulate it.
In their shoes I would keep the picture stored in my PC, possibly with an external backup, and at least once I would jerk off looking at it.
Last but not least I have a few other stories of showing sexy pictures of my wife to friends.

I've shared mine with a couple of friends. She is very flirty and they commented on it so we made some trades.