The Captain is with the Cadet on this...it sounds like your wife is rolling through the MLC. However, her actions and their effects on you can trigger your own MLC.
I think you've summarized your situation quite nicely. Put another way she wants you to accept her (and her limitations) she just doesn't want to reciprocate.
The Captain
Last sex: 04/06/1997 Last attempt: 11/11/1997 W Issues "No Means No" Declaration: 11/11/1997 W chooses to terminate sex 05/1998 I gained 60, then lost 85 pounds. Start running again (marathons)