wife first time maybe last

I am not an expert but, i have a lot of experience.

my lover is married and we are together for 14 years now and it started because my best friend wanted me to have sex with her, many many times he orchestrated our hookups, and eventually we just made our own schedule and times and he knows we do but we never tell him any more… he doesnt have sex with her any more for nearly 8 years now.
what i observed with her is that even though he gave her permission, she is rooted in conservative tradition, and as in the beginning she couldnt believe he wanted her to have sex with another guy… she still harbors fear that he will change his mind or that she will hurt him.
Judging by your comment that she hasnt done it since, leads me to think perhaps she is somewhat the same except the extramarital sex doesnt burn her flame as brite. and her denial of doing it in spite of what he said, would seem to be a natural reaction in order to avoid conflict or hurting you and your marriage.
My lover could never get her mind around him wanting it, but it really had me studying this whole Cuckold issue, and understand it as best I can. i am not a cuck, but i am the other man, the lover, and I am very careful to the needs of him and her… i feel Blessed to have this lovely filipina that is my full blown lover for so long…

good luck man, and peace to you and her.