I had the urge to jack off in my buddy's wife's bikini bottom while my wife was sleeping.
Why would you jack off to your friend's wife's bikini bottom?
Because I wanted to see her reaction, but what she did next was worse than I expected
Of course the reaction from her would be extreme. What you did was disgusting and an insult to her and her husband, your supposed friend. Apologize immediately if you want any chance of saving your friendship.
It's not my fault, since she said that I could jack off in her bikini bottom.
Regardless if she said it was okay or not, you still have a wife and I'm sure she would not be okay with that.