Vent!!!!

So my husband is 42 years old with a 19 year old son and 17 year old daughter from a previous marriage. I'm 22 and we just had our first baby together. However it makes me so upset that he doesn't help much with her. On his Friday's from work or just his days off in general he goes out with his friends. This past Thursday his best friend and him went to California to help our boss "move" but when I saw the pictures and videos all they were doing was drinking and playing around. Then he calls me at night saying "sorry baby, we're coming home tomorrow because we've been drinking. " He acts like if she is my full responsibility. Then when I ask him to help with some things he says "Nope. You wanted to have a baby right?" And he gets frustrated with our daughter when she's crying. Sometimes I feel like he's not happy to have another baby. Oh but he LOVES his 17 year old daughter and it makes me sad that he doesn't give our baby the same love. Our baby is 7 weeks and he changed her diaper for the first time today only because I was home at the time she needed a diaper change. I just hate that he doesn't help out and that because he's already been there he feels like he doesn't need to help me. Suggestions, advice, comments are all welcome. Thank you!