The scenario itself is not odd but I would be interested in knowing why he wants to see you lose and be dominated instead of winning and dominating another girl.
Myself, I like to see two even girls fight with the winner eventually taking control and dominating the loser. I would root for my girl but if she lost, I would be supportive as she was dominated.
I like Sasha's idea of doing a play version with someone you trust if you do not want to fight for real but you need to determine how you feel about being dominated by another woman. Would that turn you on or would that be something that you find repulsive.
And would he be willing to fight another guy for you and be dominated?