About why Weiwei's last name was Wen, people close to Xie Shang never asked this question, but those who weren't that close did. It happened at a Su Family banquet, attended by some distant relatives.
One distant aunt brought up the issue, her point being, it's uncommon for the firstborn to take the mother's surname, that's not the norm.
At that time, Xie Shang and Wen Changling weren't in the living room, Ms. Su Nanzhi replied to the distant aunt, "Haven't you heard how my ex-husband got put away?"
They had, sent away by his own son.
Only now did the distant aunt remember that particular incident.
"Xingxing himself doesn't even want to have the Xie surname."
The distant aunt: "..." Truly filial.
The distant aunt changed the subject, "Weiwei must be almost four now, right? You could have another one soon, Xiao Wen is still young, and she would recover quickly after giving birth."