As a women, its got to be hard to express your discomfort or threaten him for his actions when you're alone underwater with a limited amount of air, heavy gear and with someone so well trained and experienced in diving. How many of you would be prepared to struggle out of that position if his reaction were adverse? Now put yourself on the boat alone with that person and maybe a boat captain. If it continues on board you may have two people to deal with and somewhere out of view or ear shot of other boats. Unless it is life threatening, I would think doing nothing to simple resistence to his actions, until you step foot on land, would be the better choice in this situation. In my opinion, the OP did the right thing. Nothing, until she was on land. As for the future, and with her new experience, she will most likely know how to keep the situation from escallating.