I've done this many times.. I chat w the wife/GF (email works the best).. flirt w her and find out any of her secret fetishes.. and ill send you back the convo.. without ever mentioning you so she has no idea.
I'm a personal trainer and have had a lot of success with doing this. I have never had the wife/GF find out that her man was involved so it will be discreet.
Message me if your interested or have any questions....