last name help.....

I'm looking for advice and yes. I know it's not ideal, so if your gonna tell me I'm an awful person, just move along....my ex and I had a baby 3 days ago, and as I sit here filling out paperwork for his birth certificate I am so up in the air about his last name. Back story: we broke up a while ago, things have been extremely rocky. We didn't plan our pregnancy but didn't prevent it as we both wanted another child and had miscarriage in the past in our relationship. When I got pregnant I had sent him a pic of the test, the 4 I took. to be sure, with no response at all from him. my first Dr appt which was to confirm it, an ultrasound and registration, I sent him all the info and pics of our baby ultrasound, no response. I sent him belly shots, info, all the stuff to keep him up to date and until the gender reveAl he seemed to have no real jnterest, then.... he found out it's a boy! his first boy (2 girls from his previous marriage) he started touching ny belly here ans there but never really made any real attempt to show he wanted to be part of it. then... he buys a second motorcycle... hides it from me, ubtill, I fly out to spend a week with him in TX, we have a place in N.Y. together he is gone for work. has been for a year and half at that point. all he'll breaks loose that week. then he goes back to Utah for a couple more months for work. keep in mind when he comes home he spends his time with his daughters never including them in what's going on with his son. they didn't know I was pregnant till I was probably 5 months along. he wants our son to have his last name, I don't because I personally don't feel he has proved himself through the pregnancy at all. I am thinking either mine or hyphenating it. am I wrong? Since he has proven countless times that I am on my own with him. .