Chapter 891: The Scum Is Homesick 

Fei Yin sent Fei Yinzi back to the Xinfaxian Sect because he felt sympathy, as well as wanted to compensate, Fei Yinzi who was homesick. If Cheng Sheng didn't know Fei Yin in their other lifetimes, then he might believe this. But, Cheng Sheng and Fei Yin have known each other for many lifetimes, and they are also lovers. They have a tacit understanding between them. So, how can Cheng Sheng not know what his lover is really like? 

So, Cheng Sheng knows that this is just Fei Yin's excuse to send Fei Yinzi away. Not only would Fei Yinzi not be able to disturb the two's time, but Fei Yin also could set up a good image for himself to the Shanliangde Sect, especially its disciples who felt sympathetic to Fei Yinzi who was bullied by Fei Yin before so they hated him, and doubted, Fei Yin. With Fei Yin 'fulfilling' Fei Yinzi's wish to return home since he is feeling homesick, Fei Yin becomes a good person in their eyes again.