Discovering latent anger

I don't really have expectations when it comes to family. Growing up, my family was rather disjointed. I know my father's name, and where he lives, and I saw him once when I was in the sixth grade, but not since. I haven't lived with my mom since I was 12. I lived with my grandma for a while and then my aunt and uncle.
Since I have been married, my family situation has gotten much more stable and I have made it my number one priority to make sure that the girls have the sort of family growing up that I always wished I had. My family has gotten closer and we have huge holiday dinners at my house just like I always planned would happen.
Maddy and Abbey spend a lot of time with their aunts, uncles and cousins, on my side of the family. And while we have our issues and own our fair share of dysfunctionality, we all come together and support each other when it comes down to it and we enjoy each other and we keep in touch, and I can't imagine my mom going an entire month not seeing her grandchildren, let alone a month.
My entire family has not only made plans to donate blood for Isabelle, if they are physically capable, but to do so here to celebrate her life and her birthday. My mother and brother are using vacation time to leave work to be here. My sister-in-laws and brothers are taking the day off to support us.
Most of my friends, who are not related to us, are taking time off to support us.
I find myself again seething on the inside by those people who should be more involved in our lives than they are. I find myself resenting the people who can't be bothered to interrupt their days filled with book reading and travel to come here, where Isabelle lived for 3 weeks, and do something, anything for her birthday. Who can't be bothered to call and see if we're doing okay. Who can ignore our phone calls for 6 months, returning only 1 of over 20 calls. Who sends birthday cards to their grandchildren with the name spelled incorrectly. Who calls me 2 days before Isabelle's birthday to talk to me about the stress of buying a dress. A dress.
But what makes me the maddest is that this weekend and at every holiday and most likely again May 20th, my husband will be alone with my family. They love him like they love me. They consider him one of us, but it's not the same. We're not the ones who have known him since he was born. We're not the ones that held his artery closed when he cut open his wrist on broken glass trying to steal a coke, and almost died. We're not the ones who knew him before he got freckles. We're not the same and we're not enough. We know that, and we try, but we can only do what we can do, and unfortunately we can't change what they do.
And that makes me the maddest.

*****This is an addition to the original post******
I was very mad when I wrote this. I try very hard not to post when I'm so mad, but I had to get it out. I don't know why these individuals behave this way. Maybe it's too hard for them to see us or have interaction with us. Maybe they've shut us out because it's too painful to speak to us. I don't know. I can't put forth the energy to find out. I would like to think that I would suck it up for the sake of my loved ones and be whatever they needed me to be. Maybe I wouldn't, I try not to judge. But I'm really tired of seeing my husband be disappointed. I'm really tired of explaining to the girls why things are this way. I'm just really tired and mad and tired of being mad. Ignoring us and what we're going through is the equivalent of ignoring Isabelle's existence, and I can not stand that. She may have only been 3 weeks old, but she was my daughter and I held her and loved her, and my heart, my life, my faith, my confidence, my foundation is broken. Broken, and you can't see that through the fog of self-absorption you put out there. So officially today, I am done. Done trying to rationalize it, done trying to make excuses for you. Done.