Question About purse Splits: Please Answer

Can someone answer this question.......... Lets say you are a fighter, and you make $40 million a fight right. The world wants you to fight a guy who only makes about $ 20 million a fight.( after ppv) Your purse for this big fight is around $50 million (only $ 10million more than you make) Your opponent wants 50/50 so his purse is also $ 50 million( $30million more than he makes) Keep in mind your opponent is also suing you for millions. You can make another $ 40 million purse fighting Cotto. Your opponent can make $ 20 million fighting Bradley. Doesn't it seem like your opponent is gonna come out of the negotiations way better than you? I mean.....your opponent will make $30 million more than he ever has while you will only make $10 million more than you ever have. Plus once he wins his lawsuit against you, your opponent will get a few more million. So What is in it for you to fight this guy with a 50/50 split + a lawsuit? Seems to me like you could continue to make your $40 million a fight and say screw the other guy. He needs you more than you need him in my eyes.