Aggressive jealousy.

Caishen felt quite silly for being irrationally angry. This was unlike him but he was not very appreciative of the way she was laughing with Aang Yu Chen. He was another one with the right keys to her laugh factory. He had witnessed a few hahaha's while making his way to her. 

"Ah, Aang, this is my husband, Zhang Caishen." Unaware of the emotional turmoil that Caishen was experiencing, Alix went on to introduce them to each other. 

Caishen nodded stiffly, acknowledging his position. To further cement it, he took one of Alix's hands in his and interlocked their fingers. 

His actions puzzled her a little bit but she didn't dwell on the reasoning behind them.