Am I obligated to name my future child after my fiance?

My fiance is the fourth in his family to acquire the 'family name.' We don't have kids yet, but I'm already wondering... am I obligated to p on the name to my firstborn son? I don't want his family to be angry or upset with me, nor do I want to halt a family tradition, but it doesn't seem entirely fair to me that I don't really have any say in my own son's name. The name is nice (Robert), but it's extremely common and the only shortened version of it that I like is my fiance's name- Rob. I would rather pick something more unique and original, but I also don't want to cause a conflict or upset anyone. I already suggested using Robert as a middle name instead, but my fiance said if we did that, we couldn't p on the title "V" (fifth) at the end of the name. I don't think I should have to use the name, but am I just being selfish?