Dealing with the Step-kids Mom

Do you have step-children? Does the Mom bring the kids to visit? Does he call her house to speak to the kids? Does he write to her about them and she writes back? Did she ever just show up to visit without the kids? Send pictures of the kids but there are more pictures of her than them? What?...How do you deal with that ex that just wants to make herself known. You may trust you man but how do you deal with her, especially since it is very sensitive for your husband to think about not being able to see his kids, so he deals with the ex going a little over board. Let's talk about this one, it's a BIGGY!