As this couple is so wonderful, of course there must be a CP name for them. Apparently, the confirmed moniker is RuGu according to the Chinese boards/communities. @CloudA and @ajoke shared the rationale behind RuGu:
liu yuRU and GU jiusi.
一见茹顾 is the same pronunciation of 一见如故. Meaning :The first time they met, they were like old friends or they feel familiar with each other at first sight . Describing a destined love in this drama's context.
https://mydramalist.com/72599-chang-feng-du#comment-13573767