FINALLY my best friend fucked my wife

Whose idea was it for those two to get together? Has he always been interested? Was she attracted to him? Or was there some convincing involved on one side or the other?
Just the opposite sex, two people getting to know each other over time, the natural juices flowing, then flirting. I knew it was happening but I tried to stay out of it, act like I wasn't aware, I didn't want to mess it up.
 
He and I never discussed it but I guess she told him I knew. My wife knew, of course, I was encouraging her to take it to the next step with him beyond flirting.
Similiar happening with wife and l. Her 2nd extra-marital dick (16 months into marriage) Wyfe found out within 5 minutes of neighbor's departure l had seen/heard portions of their lovemaking. She relayed the news to the neighbor a week later. The next time l saw him he fell all over me with apologies. l answer him that l loved it. Thought it hot as hell. Commiserate with him on how well she performs fellatio, and the truly wondrous pussy of my beloved wife.
My reaction dumbfounded our young neighbor. (7 yrs the junior of our seductress)