Maybe sine Jian Yi's so facetious Xi like doesn't believe the story? Like what if he thinks he's just joking and won't tell him seriously what happened but no, he was actually kidnapped. :o
I think Xi Xi was hurt because Jian Yi disappeared without telling him nothing, where did he go, what was he doing, if he was safe, nor how to contact him... Or maybe Xi was very worried and doesn't know how to behave when Jian Yi comes back out of the blue, after years of absence... I also believe Xi is angry because he knows something important happened and Jian Yi is not telling him, but acting as if nothing was wrong
Xi is getting more and more gentle with Jian Yi these past chapters. But if that's the case, why did he became violent again when he meets Jian Yi once he finally reappeared? Is it because he was hurt when Jian Yi suddenly left without a word? Although, it wasn't Jian Yi's decision to be kidnapped by his father but Xi doesn't know that.