Update.....
Went out for drinks after work last Friday and thought I'd take the opportunity to try and arrange this meet up for my wife and him, started by making small talk and bringing up my wife alot (wife texting me through out telling me just to tell him out right) I'd started to chicken out a little thinking a can't do this when my wife texted and said to tell him that she was moaning about me being out and to start showing the messages.
So at that point I started to explain that the wife wanted me to go home as she was bored etc, she was sending me messages saying 'bored on my own' and 'I'm super horny, come home and fuck me' I was showing him the messages and replied saying I'm with my boss I can't just leave yet.
She replied and said bring him back with you we have plenty of beer and I'm sure I can entertain you both.
I showed him the message and made the offer to come back to the house, he was hesitating saying I don't know I think it's just best for you to leave so I thought ok he's not up for it just leave it.
I texted the wife back saying OK on my way back but on my own.
She quickly replied and said just show him the next message.
Message was: come back please...I really want to entertain you....
At this point I had no other choice but to explain to him what was happing and after a little chat we were on the way back to the house.
Within 40mins they were fucking, I was surprised that she did not insist on a condom, I was so turned on watching his cum dripping out of her pussy and they allowed me to clean her up.