Deal with her? You can only do the two of these things: either make her understand that it's alright if she wants to be friendly and meet you guys normally and have conversations with you or find a way to jettison her out of your lives altogether. Irrespective of the kind of relationship your husband and his ex-wife shared, it's history now.
To make sure that your family is happy and that you don't have to deal with unnecessary relationship complications, either she stays friendly (in a detached- attached manner) or she gets off your life completely as it was intended to be. Anything more than this is headed straight for trouble. You don't want that, if I am guessing right.

Talk to your husband and/or the ex-wife and try to have a conversation. Move to another place if you can and then the distance will help.