So most hospitals will automatically assign the baby the mothers last name until you do the paperwork which they usually won't ask for until they are born. My husband and I don't have the same last name because we planned to both hyphen but it was during Covid and we were having issues with social security accepting our documents. So when my son was born his last name was listed as mine. He has both on his birth certificate and social security card, but we had to correct it a bunch of times in the hospital. So the petty part of me say tell him "well he'll be given my last name either way so it's up to you if your name gets to be on there at all". However that's probably not going to help.
When I had this conversation with my husband before we got married I told him: My name is important to me and I will not give it up. There isn't really room for discussion about it. I'm happy to add your name, but I won't give mine away. I want my children to share my name because I have a lot of love and pride in my family and our last name is slowly fading away (not just in my family but there aren't that many of us in the US in general bc its an uncommon name). I want my kids to carry on the name. He was fine with me hyphenated but he was little jarred about kids. He did come around when I told him I didn't want a different name than our kids, so he decided he'd change his name too that way we'd all have the same name- we just have to actually get around to changing our names now.
I have no advice but I just want to say I support you and your decision! I think it's very smart & you have a valid reason of feeling the way that you do ❤️ hope he comes around