WHY DOESNT HE WANTTO LOVE OUR BABY?

I'm extremely heartbroken right now and feel like I'm in a very uncomfortable situation with my fiancé and our kids. I have a 3 year old step daughter and a 1month old newborn... my entire pregnancy, I never felt like my fiancé was happy about bringing another child into he world, just bc he never seemed excited or touched my belly unless we were in front of family and he was idk, he was all of a sudden "interested"... then when we return home, he never mentions it. Some days were better than most and we remembered why why love each other but the arguing has never gone away. One of the most attractive things about him when we started dating was how awesome of a father he was to his little girl. I thought he was the best dad to that girl and his heart was huge.. after getting serious, and falling in love with him and his daughter, I couldn't wait to expand our family. Even though it happened a little sooner than we expected, she is the best thing to ever happen to me. I'm overwhelmed!!! I just love my baby girl with every peice of me. & although I love becoming a new mom, getting the hang of things is so hard! At times I have been sleep deprived and irritable bc after I had my daughter he was helpful the first 2 or 3 nights, then he just wasn't.... he seems like he has no interest and he's nothing at all like the father I thought he was and that I witnessed with my stepdaughter. He has never said one sweet thing about our baby... he never asks how she's doing throughout the day while he's working but constantly asks about his other daughter. He doesn't try and bond with her or say sweet things to her. He's mentioned that he feels like she's spoiled bc she loves to lay on me and she's a cry baby... she's 1 month old. 
I am not trying to take this out on my stepdaughter, but it's started to make me resent him a lot... and I haven't been bonding with her as much after having my daughter, due to me getting the hang of things. Everytime we discuss it, he says he'll work on himself but he just doesn't.. I told him I would work on my bond with my stepdaughter and I have. Today I spent a lot of time with her but for some reason he has been short with me all day. I went to get my hair done earlier since I haven't done anything for myself since I had my daughter. My mother in law kept the girls and then he went by there to hangout (I guess) well this was he longest I had been away from my girl since... before She was conceived (lol)... so I was texting him and he wasn't texting me back...I ask him what wrong and he says nothing... then I asked him if he could bring me tum since my stomach was killing me. No text back... I asked him to send a picture of my daughter to me.. no text back... so I just text his mom to get updates on the baby. When I get done, I go meet them at my MIL house and he was mostly quiet and in his phone the entire time.. I asked if he wanted to take the girls to some Mayfest here in FW but he says no bc it probably pack.. k...well we leave In out cars and I told him I was going to get us mochi ice cream doe the street (just trying to be nice and offer something that we could do as a family)... well I get the ice cream and got home after him and stepdaughter...I show her the ice cream and she super excited (I don't buy sweets EVER)...then he says he's taking her to the park but knowing that I want my and the baby to go out  someWhere too, hence asking about the fest! Well the leave for the next3 hourse... that just made me mad bc once agai ,  we are not included in his thoughts or plans...  
it's getting unattractive the way he just doesn't care for our newborn as much as he does my stepdaughter.. I want my baby to have a bond with him too, but he's uninterested. Idk what to do with my family...