jb, just wanted to post a bit of a reality check here.
You indicated that you let your W have S for a Sunday and rationalized it as though you are being generous in advance of you needing her to be flexible on schedule in the future.
That is one thing I used to do and finally admit that any generosity on my part is generally not reciprocated.
I'm not saying to not be generous, I'm just saying don't expect reciprocation.