This is very well put.
The current state of their marriage is - status quo - in certain respects. Charles has always held the power situation in this relationship; most affairs are more about power and less about sex, yet marriages tend to find a power equilibrium. Even after their marriage, Camilla holds the current wealth, power and position due solely by the grace of Charles. She must dance to Charles' tune, probably more so than during the very brief time that she was single, after Andrew divorced her.
While her divorce settlement from Andrew was in keeping with Andrew's position as a miliary man of moderate means, Camilla was at that time the recipient of a settlement from Charles that made her independent for the first and only time in her life.
Camilla certainly bettered her financial situation by marrying Charles, and the financial situation of her children. (It's wildly disingenous to suggest that Camilla was blind to the monetary advantages of such a match.) But I think that even she knows that it's an unequal equation. An unequal marriage, right down to the titles.
It's a bargain that needs to be kept, however, in this case; the bargains that were broken to get here demand it to be so.