I remember reading a story like this, but haven't been able to find it again. I'd love to find it...and more like it. The story involved a husband and wife who were upset with each other. She wasn't happy that he wanted her to be more provocative in public and he thought he was being cold and unreasonable. With one of his friends, she decided to push a little...convinced that her would cave in and give up....and not like seeing her go further with another man. The tension built as she went further and further with him...each daring the other to cave in and say "stop". At one point, she is positioned above the friend...and he is ready to penetrate her...when the husband pushes her down onto his cock.