I will honestly say I didnt think i'd get so many positive responses but thanks you guys. My problem is that I am very close to the wife, and even walked her down the isle for their wedding, but in the same instance, I know he cheats on her and so does she. I don't want anything more from him than to just hook up like he asked then on my way to continue on with the friendship. Now what am I gonna do if he gets hooked? But I guess i'll see when that comes around.
If they both cheat on each other, then I guess you can feel less guilty about the whole situation. As a fantasy - servicing a married man is hot in theory but I would feel like an arsehole if I got found out about the whole thing and it caused trouble.