First, the custom of naming mostly follows the father's surname. In the National Surnames Report 2020 issued by the Ministry of Public Security, the ratio of surnames with mothers to surnames with fathers is 1: 12. As can be seen from this ratio, not many people take their mother's surname, while your boyfriend's surname is Xu and his mother's surname is Wang, both of which are hundreds of surnames.
1
Most of these surnames have their own family and genealogy, and in genealogy, they are all inherited by men, so these two people will belong to the group with their father's surname.
So it's normal that he doesn't take his mother's surname Wang or Xu.
Second, his mother's surname is Wang, because his mother is married, not an adopted wife, and has no husband's surname. In our hometown, daughters with their father's surname are all married women;
And those who take their mother's surname are mostly recruited for various reasons.
2
Your boyfriend's mother is not surnamed Xu, which means she is married normally, not a door-to-door son-in-law.
In modern times, all women have independent surnames, and Guanfu surnames are even less. She is no longer Wang Xu, and she is no longer. In the genealogy, there is also a famous surname, not the husband's surname, called XX, which is the progress of society.
Third, there are only a few reasons, all based on the mother's surname.
Reason one: ask the son-in-law mentioned above to take his mother's surname;
Reason 2: Parents divorce, children are raised by women, and divorce has nothing to do with age. Although the blood relationship of the child is still there, the surname on the household registration book has been changed;
Reason three: local customs, following the mother's surname. For example, some areas in Nanning, Guangxi, follow their mother's surname. After they leave society, some people will think that others have their father's surname. I have met such a friend. Her surname is rare, so I won't talk about it here, so as not to have a lying gun with the same surname.
three
Reason 4: Both parents are only children and have agreed to have two children, one with the father's surname and the other with the mother's surname. This situation is normal in modern society.
Therefore, the boyfriend's surname is different from his mother's surname, which is not a big problem. Of course, the premise is that he treats her sincerely and does not fabricate his own identity information.