Of course not all stepparents are bad, but anytime the trypical two-parent bond is broken through divorce, affairs, illness, alcoholism, mental illness, or even the adoption of a new child....the family dynamic changes. And usually not for the better. No child wants to feel the rug pulled out from under them, but some marriages weren't meant to be. Having a stepparent isn't always a disaster but it's not ideal. That's life, not ideal.