Me and my wife had a few threesomes and they were all with good friends as she has no interest at all to meet with strangers
She fucked 3 different friends. With two of them things went fine. We even had repeat threesomes and had a lot of fun. With the last one though things got awkward. He started to avoid us for a while. My wife tried to talk to him a few times but he always responded that everything was oke etc, but he still avoided us as much as possible. This changed after he got a steady girlfriend, now things are a bit normal again, except that he still never meets us alone.
I guess he felt uneasy around us after what happened.
So things can work out for you and they can go bad. That's always a risk when meeting up with friends I guess.
In your case I would start by checking with your wife if she's interested in any of your friends to begin with. And when (if!) she has one or more candidates you can start trying out those friends by sending them sexy pics of your wife. When they react with a 'WTF' you can pretend to have sent them by accident. Then you can proceed by asking him if he liked what he saw...etc etc....
This way you can check out if he shows any interest or none at al (believe me, it happened with another friend of us!)