I'm not sure what this means or where to go from here!

I'm not sure what this means or where to go from here!
I recently went away on business, whilst I was away a good friend of mine stayed over as he was visiting on business!
This friend has done a massage course and whenever he visits offers my wife a massage. After a couple of bottles of wine my wife was relaxed and she accepeted his offer of a massage.
As luck would have it, just after the massage finished I text my wife to say I had arrived safetly and asked what she had been doing. She replied by telling me my friend had turned up for the night - not an unusual occurance - and had given her a great massage. At this point I felt a turn in my stomach as I thought of her laying at home naked being sensually massaged by another man.
Having often encouraged my wife to show herself off more and shared the occasional pictured with friends, I was not surprised she had stripped off for a massage, but I thought I would try my luck and ask if I could see a picture of her all oiled and hot.
After several text messages and a failed MMS message - I never got to see what she sent, but wish I could - she told me she would pose for a couple of pics, but how far did I want her to go?
This is the first time anything like this had happened, so I played it cool and said a few discrete poses would be good to start, but if she wanted to take it further I would love everything she did!
At this point, I decided to leave them to it and get some sleep. I lay in my bed thinking of what my friend was doing with my wife whilst I lay there alone.
The next day I hurriedly opened my email with excitment. My friend had taken a nice selection of photos, until now I had only ever persueded her to let me take topless photos, however last night she had stripped naked for my friend and let him take pictrues. WOW.
It was a few hours before I finally got to talk to her about what had happened. My stomach churned as She told me she had been reluctant to strip, but my friend had helped by getting naked with her! Good lad I thouhgt! I asked her if she liked what she saw? but she wouldn't answer. She said he had been aroused whilst he photographed her, and she had allowed him to touch and kiss her, but did not want to touch him or let him wank over her. :-( although she thought he would of done anything she had asked ! No shit I thought to myself!
Over the next couple of weeks, the text messages got hotter as I described what I wish I had seen them doing. Why I wanted her to experience another man and how I would love to share her with a friend.
She accepted that she had turned on my mate and her inhabitions and doubts about her body were discussed. She even went as far as to send a couple of the pics to a couple of male friends to see what they thought.
However, now I have come home, she has gone cool on the idea, and doesn;t even join in conversations about sharing her, much to my disappointment. She tells me she only did this for me as I was away and lonely. I have tried to tell her exactly how hot she is, how good the experience was and how I want to repeat it either with me there or whilst I away again. This time with her being a little bit more daring!
How can I encourage her to try again? I am desperate to see her with another man for my enjoyment.