Here's a thought-provoking idea from a blog (and newsletter) I really like called The Happiness Project. Are you jumping the gun and consistently characterizing the actions of the mom or stepmom in a negative light, before you really know her true intentions?
Worth a thought!
Great idea; after dealing with ongoing negativity, it’s very difficult to not automatically assume that every word or action is the spawn of some diabolical plan. I believe there is also danger in giving benefit of the doubt to someone who does not deserve it, however.