He was surprised that Zhao Yuning was bringing up the past. Back then, she had suddenly broken up with him, saying she had fallen in love with a mixed-race man. The man lived in California and was an exchange student at their high school for a year. They had only known each other for less than three months. Zhao Yuning complained that he wasn't romantic enough, didn't say sweet things, and didn't care enough about her, so she fell for someone else.
That's what she told him. After the breakup, Zhao Yuning went to the US with the young man, but they didn't end up together. Tang Shuwen became suspicious and felt that the situation wasn't that simple. But he didn't want to guess what the real reason was. All he knew was that Zhao Yuning was very determined to break up. He was also a proud man and would never give up his dignity to beg her to come back.
After they got back together, neither of them brought up the past.
Now that she mentioned it, he wasn't interested.