I don’t have personal experience with this issue, but I understand your frustration. You 100% should have a say in your child’s name!! Though I also understand your husband’s perspective – I would be less convinced if he just wanted a “Junior”, but when it’s been going on 3 generations already, I understand why he might feel strongly about continuing the tradition.
[name_f][/name_f][name_f]My[/name_f] piece of advice would be to consider using both his first and middle name as middles, if you’re open to it, and then choosing a new first name you like. So if he’s [name_m]John[/name_m] [name_m]Thomas[/name_m] [name_m]Smith[/name_m], your son could be [name_m]Levi[/name_m] [name_m]John[/name_m] [name_m]Thomas[/name_m] [name_m]Smith[/name_m]. That way the full family name still gets passed down, but you also get to choose a name.
[name_f][/name_f]I also think giving the baby his middle name makes sense – my parents did that, as my father is a [name_m]Jr[/name_m]. but his first name is super outdated and my mom didn’t want to use it for a son (plus it has no nickname options besides the one my dad uses, so it would’ve been confusing). They ended up giving my brother the same middle name as my father/grandfather and chose a new first name that my mom loved.