Step - parenting take two people and they both have to have the child's best interest at heart. It is so difficult when so many adults are involved and children become confused. Even the older ones. It is a constant struggle.
When I raised my step -son, at first, his Mother tried to put a wedge between us. I concentrated on my step-son. I left his mother AND father out of "our" bonding relationship. I NEVER put down his/her Mother or Father for that matter.I poured my love over him because he was only 5 years old and needed SOMEONE to love him unconditionally. I was fair and firm, the same as I was with my 2 girls. He wanted to go live close to his Mom after he finished his education(firm)and I am thankful that he had that opportunity. I watched him go and was proud to send a beautiful, kind, educated grown man her way. Very proud!!!
I will say this over and over again...it is sometimes difficult to "love" another woman's child if you are a step-parent. Difficult yes, but not impossible.
Adopted parents do it all the time. They fall in love with "others" children. Would they love these children less if the parents were involved? Good question.
It takes a strong person to change things around in your favour(peace).I wanted to have my step-son turn around in later years and see that I loved him unconditionally, no matter what his Mom wanted him to think. I'll bet my life, if she ever said an unkind word about me now, he would put her in her place and say it with a great respect.

All I can say to anyone who is in a bad situation with a step-child is continue to show love, and respect with a bit of firmness mixed in. Take it upon yourself, to fix it, especially if Dad's don't really know how or want to...some day it will return...

Pugma, perhaps you could have said, "B is not a very nice word and I am disappointed that you had to hear your Mom say such a thing. You know I love you don't you? And then hug her and say, Let's you and I be good friends, come on let's go do this(insert your own activity here). Twelve is a difficult age as it is. Knowing someone cares about you is what's needed then more than ever.
I appreciate your dilemma and wish you the very best...but if you want my opinion, try kindness till it kicks in. I have a feeling it will work for you too. You have nothing to lose, just don't quit trying. Try to put yourself in her situation and tell her you understand. One day when she walks down the aisle, you can stand proud of having been there for her - no matter what. Believe me, she needs you, they all do.

Sorry for the ramble, but I know it worked for me...so why not you?

Your baby needs a comfortable, peaceful place to start life in...and you deserve it too. I hope and pray that things work out for all of you.

Welcome and stay posting. We need to hear more about your little one on the way.

God Bless
chick