Beautiful.

This is great post. We have had the same debate at our house and for much the same reason. Stepmother, as a title just doesn't feel right to me. I say stepmom, it sounds better to me at least, nicer. I also prefer to use A's mother instead of husband's ex-wife to refer to her mom.
In the beginning my mom was introducing A as my daughter's husband's daughter, a mouthful.

Thank ya'll for all the positive feedback. Its good to know that I am not the only one trying to figure all this out.