I do not mean to imply that her obligations are any less important than mine. Although, we truly only ask when it is necessary, an occasional (one in four years) anniversary dinner without children. If it is that much of an inconvenience, we would prefer she just say no and leave it. Any advice on how to approach this with her? We are very frustrated.
Answer: Best approach: Stop asking.
It would be better if she just said no, I agree. I also get that you want Grandma and grandkids to be close. Her huffing and puffing, though, are the equivalent of no, with the added message that she feels bad enough about saying it that she'll go out of her way not to.
I'm not excusing this (it is spineless), just explaining it - though I think it's something you already know.
If you don't have even a short list of sitters you can hire, you need to develop one. If you do have a short list and occasionally everyone is busy, either postpone your dinner to a workable night, or, OK, ask your mother-in-law - knowing you'll get 18 excuses and possibly no sitter. Part of any "wonderful" relationship is making allowances for the occasional nonwonderful thing that's part of the package with every person on earth.
That offhand remark, about "things she has going on that may be impacted by a few hours with her grandchildren"? It reveals a whole worldview: that grandmas put themselves aside for their grandchildren.
It is lovely when they, and grandpas, do. However, some grandparents are through with child care, done done done, and they - not you, and not Norman Rockwell - get to decide what kind of grandparents they'll be.
For dinner, for drinks, for vacay, they're in. Pattern alert.
E-mail Carolyn at firstname.lastname@example.org, follow her on Facebook at www.facebook.com/carolyn.hax or chat with her online at noon Eastern time each Friday at www.washingtonpost.com.