Nonsense. Read the OP. This woman is 27 and she herself says this is the FIRST real opportunity (at least as she perceives it, I'm not so sure the "man" she is dating is even contemplating marriage yet) for a possible marriage opportunity she's EVER had. To an age-appropriate guy who, apparently, would be fine in all other ways (she has mentioned any negatives, at all, about this guy) for a huband, EXCEPT if he wants her to take his last name (i.e. behaves normally as most men would expect their wives to do when getting married to them). And what's her reason for wanting to preemptively sabotage what might be her best opportunity for marriage (since she's never had one before, and she's already 27)? Because GRANDPA threw a tantrum. He must be a pretty WEIRD grandpa to throw a tantrum over the possibility that his granddaughter might be thinking about taking the last name of the man she is thinking about getting married to. There's all kinds of extended family psycho drama underlying this OP.