I know we've discussed Mathilde on another thread, and I was rather dismayed by what I read about her, having only read her own words which of course painted her in an attractive light.
Still, I would like to think that she was a pleasant enough of a mistress for Nicholas, and that their relationship demeaned neither person.
Perhaps, as time went on and Mathilde realized she was to be passed from one man to another, she developed an especially avaricious character. Given that she had a profession other than courtesan, however, and was recognized as being one of the very best dancers in what was considered the ballet capitol of the world, I question why she felt it necessarily to be so greedy and duplicitous.