I just left my fiancé. It was the final straw for me. He got mad at me for something really small and didn’t go to his sons 1st bday party. He hasn’t changed the baby’s diaper since we left the hospital. He never spends time with his son. There are days when he comes home from work and won’t even acknowledge him. He doesn’t help out financially I stay home and take care of the baby. My mom is the one who helps me buy all the stuff my baby needs. It’s been three days since I left and he hasn’t asked about his son once. Now here is where it gets tricky. My sons last name is neither of ours. My ex fiancés father was in a gang and changed his last name to fit in. So my ex fiancé got stuck with this random last name. My fiancé told me he is going to change his last name to what it’s really supposed to be so he wanted our son to have that last name. It’s been over a year and he still hasn’t gotten his name changed. So right now my baby’s last name is neither of ours. Now that me and him are not together I can honestly say I don’t know if he’ll be in my sons life. So I’ve been thinking of changing my baby’s last name to my last name. Any thoughts? Is this self of me? And am I legally allowed to change it without his fathers consent? (My baby’s birth certificate is still in the office.my fiancé never wants to go with me so it hasn’t been signed)