2 Last Names - I don’t want it

So my boyfriend is going through a process of adding his fathers last name to his mothers last name. I met my boyfriend years ago and have always visioned myself taking his mothers last name(because it wasn’t until a month ago that he wanted to add his dads). Here’s the thing… I don’t want to take his dads last name when we get married.

One reason why I don’t want to is because after being with my boyfriend for 6 years, his father barely knows me and I barely know him. Another reason is because his father manipulates tf out of my boyfriend and his siblings. Since I’ve known my bf, his father has done so many awful things to his kids and I can’t sit right knowing I would be giving up my last name that I love to add his. I want to take his mothers last name because 1) that’s the name I’ve known him by for 6 years and 2) his mother has shown me that she really wants to know me and makes me feel welcomed and apart of the family. His father on the other hand, hasn’t shown me any sort of welcoming until this last year and it doesn’t settle right with me. I have tried to build a relationship with him but it doesn’t seem genuine from him and that’s a big thing for me.

It means a lot to me to change my last name. I know I can keep my last name but it doesn’t fit with my boyfriends at all and I rather just take his mothers last name. However, my boyfriend wants me to take both. What if I don’t want to? What happens when we have kids? What if I have only one last ans and my kids have his 2 and it just doesn’t make sense?

I can’t be honest with him on why I feel this way. He doesn’t understand that the real reason I don’t want to is because of how his father has treated him and how we don’t even have a relationship - it just doesn’t set with me to take his fathers last name, give up my own, and live with it.

What should I do? What happens if we have kids?