What should a woman do?
Only once in my life did some guy grab my breast without warning, and my immediate reaction was to punch him in the nose and send him backwards. He never bothered me after that. Can't imagine why anyone would wait years to complain. However, punching Arnold in the nose would have been a different thing. The humiliation would have been deafening.
Still, I'd think he was a jerk and in this day and age, I'd report it.
BTW, if he has pursued this behaviour for years, I doubt he'll change much.....for long.