Anonymous wrote:You can't actually stop her from moving closer to you, so I would given up the idea of controlling something you can't control. My first step would be to sit down with your husband and have a frank talk about what you will and will not accommodate this summer (e.g., if/when your stepfather passes away, you'll be inviting your mother for a long visit and you won't be available to entertain his mother; his mother can't come over during the workday because it's too disruptive). Then put it on him to put together a plan for how the summer will work and to communicate that to his mother. If she still comes, hold your boundaries firm and let your husband deal with the fall-out.
This is good advice. Its really the only thing you can do. My concern would be that your husband would say "yes" now, but back down when it actually happens. As in, you come home from the store and see them sitting there waiting for dinner and your husband mad at you that you are not happy for unexpected dinner guests.
Also, if you have a nanny, I'm confused what kind of help they will be offering (or think they are offering?) Weekend babysitters? Homework help?