You can not honestly believe that she deserves half of what he's earned? Unless she was a part of the deals and making the beats, there is no way she deserves 400 million.
Like Eddie Murphy once put it, it is all about perspective. Half is still half. If you only had one dollar to your name and you had to give someone 50 cent, you would be pissed.
The Dr. Dre of 202 is definitely not the same Dr. Dre of 1996. I am sure he could not even fathom earning a quarter of what he has til this point.