I hope you don't mind this question and please feel free to decline to answer if it is too personal. You mentioned to me in a post about a month ago that you also have a stepchild(ren) and that I will feel like the new baby is mine (thanks for your very kind post, btw!)
My question is, did having a baby with your DH improve your relationship with those stepchild(ren)? I can see being totally touched by the love beween the children develop and the family solidifying more. I can also imagine new complications arising.
Well my step-daughter is 20 years old but I have known her since her early teens. She has her own little baby now and does not live in the same state as us so we don't see her very often. Her and I shared the unique experience of being pregnant at the same time together. But our relationship has not changed since the birth of DS. And since she has her own baby she wants us to focus on her baby.
I totally feel like I am 100% the mother of my DS. In no way at all does it feel like I am a step-parent to him. And I don't feel at all that my DH is more of a parent because he has a genetic connection and I don't. He feels like my baby in the same way my OE DD felt like my baby.
I do think a new baby could help to solidify a blended family though. You just have to make sure everyone feels included and loved.