Planet you name it, is very much like earth. Almost identical. However there is one major difference. On this planet the woman have all of the stereotypical traits of a male(Stronger, main wage earner, aggressive, strong sexual appetite, or whatever. They however are still mostly attracted to men. The men who have all of the typical traits of a woman(You can help here).
About one in a million men and woman have a disease which makes them like their sex would be on earth. The woman not used to being domiated sexually, or not used to having their asses kicked by a male no less. We can add or take away from these examples but the story could develop many ways. Either he is captured by a goup of them to be enslaved before he discovers a way not to just escape but to do to them what they have done to him. Or at least most of it. lol. Please let me know your ideas if interested.